# Cytology of the Ear and Skin in Veterinary Dermatology ## Quick Answer - Collect ear and skin cytology samples before initiating any topical or systemic therapy to maximize diagnostic yield and avoid treatment-induced artifacts. - Use Diff-Quik or similar Romanowsky stains for routine in-clinic evaluation, and reserve special stains for cases where organisms are suspected but not visualized. - Cytology identifies infectious organisms and neoplastic cell populations, but it cannot replace histopathology for definitive tumor classification or surgical margin assessment. ## At a Glance | Sample Type | Collection Method | Common Findings | Clinical Utility | |---|---|---|---| | Ear canal swab | Cotton-tipped applicator rolled along the vertical canal | Malassezia yeast, cocci, rods, inflammatory cells | Directs topical and systemic antimicrobial selection | | Skin impression smear | Direct slide contact with exudative or ulcerated lesions | Neutrophils, acantholytic cells, bacteria, fungal elements | Rapid differentiation of pyoderma from immune-mediated disease | | Fine-needle aspiration | Needle inserted into nodule or mass with suction applied | Epithelial, mesenchymal, or round cell populations | Guides surgical planning and staging decisions | ## Clinical Context and Diagnostic Role Cytology occupies a specific position in veterinary dermatologic diagnosis. It provides rapid, inexpensive, and minimally invasive information that directly influences treatment decisions. The American Veterinary Medical Association emphasizes the importance of regular veterinary examinations for early disease detection and preventive care, and cytology is a core component of the dermatologic examination in companion animals. The American Animal Hospital Association similarly supports diagnostic approaches that enhance preventive care and life-stage appropriate medicine. Cytology is not a replacement for histopathology, but it serves as a first-line diagnostic tool that can distinguish infectious from inflammatory and neoplastic processes. The clinical value of cytology lies in its ability to answer specific questions. Is this dermatitis caused by bacteria, yeast, or both? Is this nodule an inflammatory mass or a neoplastic growth? What cell population predominates in this exudate? These questions guide immediate management decisions, including whether to prescribe antibiotics, antifungals, or anti-inflammatory agents. The World Small Animal Veterinary Association emphasizes the importance of evidence-based clinical guidelines in companion-animal practice, and cytology is a foundational component of dermatologic diagnostic guidelines. ## Sample Collection Techniques ### Ear Cytology Collection Proper collection technique determines the diagnostic quality of ear cytology. The external ear canal should be examined with an otoscope before sampling to assess the degree of inflammation, the presence of masses, and the integrity of the tympanic membrane. A cotton-tipped swab is then introduced into the vertical ear canal and rolled gently along the canal wall. The swab should be rotated to collect material from the entire circumference of the canal. The collected material is then rolled onto a clean glass slide in a thin, even layer. Thick smears are difficult to evaluate because cells and organisms are stacked on top of each other, obscuring morphologic detail. The choice of swab matters. Standard cotton-tipped applicators are adequate for most cases, but some clinicians prefer swabs with smaller heads for small-breed dogs and cats. The swab should be inserted only to the depth of the vertical canal to avoid trauma to the tympanic membrane. If the tympanic membrane is ruptured, material from the middle ear can contaminate the sample, and the cytology results may not reflect the primary disease process. ### Skin Cytology Collection Skin cytology can be collected by several methods, each suited to different lesion types. Direct impression smears are used for exudative, ulcerated, or moist lesions. The lesion is gently blotted with a clean slide to absorb surface material. This method is simple and effective for lesions that are already exudative. For intact pustules, the pustule should be ruptured with a sterile needle and the contents expressed onto a slide. This technique preserves the cellular composition of the pustule and avoids contamination from surface bacteria. Skin scrapings are used for lesions that are not exudative. A scalpel blade is used to scrape the surface of the lesion, and the collected material is spread onto a slide. This method is particularly useful for detecting fungal elements and mites. The depth of the scraping depends on the suspected condition. Superficial scrapings are used for surface yeast and bacteria, while deep scrapings are used for conditions that affect the deeper layers of the epidermis. ### Fine-Needle Aspiration Fine-needle aspiration is used for nodular lesions and masses. A small-gauge needle is inserted into the mass, and suction is applied with a syringe. The needle is moved back and forth within the mass to dislodge cells, and the suction is released before the needle is withdrawn. The aspirated material is then expelled onto a slide and spread into a thin film. This technique is particularly useful for differentiating between inflammatory masses and neoplastic growths. The quality of the aspirate depends on the cellularity of the mass. Cystic masses may yield only fluid, while solid masses may yield a dense population of cells. The clinician must interpret the aspirate in the context of the clinical presentation. A negative aspirate does not rule out neoplasia, and a second aspirate may be needed if the first is nondiagnostic. ## Staining Methods and Interpretation ### Romanowsky Stains Romanowsky stains are the most commonly used stains for veterinary cytology. These stains include Diff-Quik, Wright, and Giemsa stains. They are rapid, inexpensive, and easy to use in a clinical setting. The stains produce a characteristic pattern of blue and pink coloration that allows for the identification of cell types and organisms. The staining protocol is simple: the slide is fixed in methanol, stained in the eosinophilic solution, and then stained in the basophilic solution. The slide is then rinsed and dried. The quality of the stain is critical for accurate interpretation. Overstaining can obscure cellular detail, while understaining can make cells difficult to identify. The staining time should be adjusted based on the thickness of the smear. Thicker smears require longer staining times, while thinner smears require shorter times. The clinician should evaluate the staining quality under the microscope and adjust the protocol as needed. ### Special Stains Special stains are used when the routine stain does not provide sufficient information. Gram stain is used to differentiate between gram-positive and gram-negative bacteria. This distinction is important for selecting appropriate antimicrobial therapy. The Gram stain protocol involves a series of steps, including crystal violet, iodine, alcohol, and safranin. The result is a purple color for gram-positive bacteria and a pink color for gram-negative bacteria. Other special stains include the periodic acid-Schiff stain for fungal elements and the acid-fast stain for mycobacteria. These stains are used when the routine stain does not reveal the organism. The decision to use a special stain is based on the clinical presentation and the results of the routine stain. If the routine stain shows a large number of neutrophils but no organisms, a special stain may be needed to identify the causative agent. ## Interpretation of Ear Cytology ### Normal Findings Normal ear cytology shows a small number of epithelial cells and occasional bacteria. The epithelial cells are squamous cells that are shed from the lining of the ear canal. The presence of a few bacteria is normal, but the presence of a large number of bacteria or yeast indicates an overgrowth. The normal ear canal has a small population of commensal organisms, including bacteria and yeast. The balance of these organisms is maintained by the immune system and the physical environment of the ear canal. ### Malassezia Overgrowth Malassezia is a yeast that is a common cause of ear disease in dogs and cats. It is a normal inhabitant of the ear canal, but it can overgrow when the environment changes. The overgrowth is often associated with underlying conditions such as allergies, endocrine disease, or the use of antibiotics. The cytology shows a large number of yeast cells, which are characterized by their round to oval shape and their budding appearance. The presence of Malassezia is often associated with a waxy, brown discharge and a characteristic odor. The yeast cells are easily identified on a Romanowsky stain. The treatment of Malassezia overgrowth involves the use of topical or systemic antifungal agents. The choice of treatment depends on the severity of the infection and the underlying cause. ### Bacterial Overgrowth Bacterial overgrowth in the ear is characterized by the presence of a large number of bacteria. The bacteria are often cocci, which are round cells that appear in clusters or chains. The presence of bacteria is often associated with inflammation, and the cytology shows a large number of neutrophils. The neutrophils are white blood cells that are attracted to the site of infection. The identification of bacteria is important for selecting the appropriate antimicrobial therapy. The Gram stain can be used to distinguish between gram-positive and gram-negative bacteria. The choice of antibiotic depends on the type of bacteria and the sensitivity of the organism. The clinician should consider the possibility of a resistant infection if the clinical response is poor. ## Clinical Interpretation of Skin Cytology ### Inflammatory Patterns Skin cytology can be used to identify the type of inflammation present in a lesion. The presence of neutrophils indicates an acute inflammatory response, which is often associated with bacterial infection. The presence of lymphocytes and macrophages indicates a chronic inflammatory response, which is often associated with immune-mediated disease. The presence of eosinophils indicates an allergic response, which is often associated with hypersensitivity reactions. The pattern of inflammation is important for the diagnosis. A predominance of neutrophils suggests a bacterial infection, while a predominance of eosinophils suggests an allergic reaction. The presence of acantholytic cells, which are rounded epithelial cells that have lost their intercellular connections, is a characteristic finding in pemphigus foliaceus. The presence of these cells is important for the diagnosis of this immune-mediated disease. ### Neoplastic Cytology Skin cytology can be used to identify neoplastic cell populations. The presence of a uniform population of cells with a high nuclear-to-cytoplasmic ratio suggests a neoplastic process. The cells may be epithelial, mesenchymal, or round cells. The identification of the cell type is important for the diagnosis and the treatment plan. The cytology of a neoplastic mass is not always diagnostic. The sample may be nondiagnostic if the mass is cystic or if the cells are not well preserved. The clinician should consider a biopsy if the cytology is not diagnostic. The histopathology provides a more detailed evaluation of the tissue architecture and the cell morphology. ## Practical Implementation Steps ### Step 1: Prepare the Patient and Equipment The patient should be positioned in a comfortable and safe manner. The equipment should be prepared before the procedure. The slides should be clean and dry. The stain should be prepared according to the manufacturer's instructions. The cotton-tipped swabs and the needles should be sterile. ### Step 2: Collect the Sample The sample is collected using the appropriate technique for the lesion. The ear canal is sampled with a swab, and the skin lesion is sampled with a scraping or an impression. The sample is applied to a clean slide in a thin film. ### Step 3: Stain the Sample The slide is stained with the appropriate stain. The staining time is adjusted based on the thickness of the smear. The slide is rinsed and dried. ### Step 4: Evaluate the Sample The slide is evaluated under the microscope. The clinician identifies the cell types and the organisms. The results are recorded in the patient's medical record. ### Step 5: Interpret the Results The results are interpreted in the context of the clinical presentation. The clinician considers the history, the physical examination, and the cytology results. The treatment plan is based on the interpretation of the results. ## Records and Measurements The cytology results should be recorded in the patient's medical record. The record should include the date of the sample, the site of the sample, the collection method, and the staining method. The results should include a description of the cell types and the organisms. The record should also include the interpretation of the results and the treatment plan. The record is important for monitoring the response to treatment. The clinician can compare the cytology results before and after treatment to assess the effectiveness of the therapy. The record is also important for the continuity of care. The clinician can review the record to understand the patient's history and the response to treatment. ## Common Failure Patterns ### Inadequate Sample The most common cause of a nondiagnostic cytology is an inadequate sample. The sample may be too thin, too thick, or not representative of the lesion. The clinician should ensure that the sample is collected from the appropriate site and that the sample is applied to the slide in a thin film. ### Overstaining Overstaining is a common problem that obscures cellular detail. The slide is stained for too long, or the stain is too concentrated. The clinician should adjust the staining time and the concentration of the stain to achieve the optimal result. ### Understaining Understaining is a less common problem, but it can also obscure the cellular detail. The slide is stained for too short a time, or the stain is too dilute. The clinician should adjust the staining time and the concentration of the stain to achieve the optimal result. ### Contamination Contamination can occur when the sample is collected from the wrong site or when the sample is contaminated with the material from the environment. The clinician should ensure that the sample is collected from the correct site and that the sample is not contaminated. ## Limitations of Cytology Cytology is a valuable diagnostic tool, but it has limitations. The sample is a small sample of the lesion, and it may not be representative of the entire lesion. The cytology cannot provide information about the tissue architecture, which is important for the diagnosis of some conditions. The cytology cannot distinguish between a benign and a malignant neoplasm, and it cannot provide information about the surgical margins. The cytology is also limited by the skill of the clinician. The interpretation of the cytology requires experience and training. The clinician should be aware of the limitations of the cytology and should consider a histopathology when the cytology is not diagnostic. ## Safety and Regulatory Context The collection of cytology samples is a minimally invasive procedure, but it is not without risk. The clinician should use sterile equipment to prevent the introduction of infection. The clinician should also be aware of the risk of bleeding, particularly when the sample is collected from a vascular lesion. The clinician should use appropriate restraint to prevent injury to the patient and the clinician. The use of cytology is a standard practice in veterinary medicine. The World Organisation for Animal Health provides that the use of diagnostic tests is an important component of animal health and welfare. The cytology is a diagnostic test that is used to guide the treatment of the animal. ## Professional Escalation Criteria The clinician should escalate the case to a specialist when the cytology is not diagnostic or when the cytology results are not consistent with the clinical presentation. The clinician should also escalate the case when the patient is not responding to the treatment. The specialist can provide a more detailed evaluation and a more advanced diagnostic workup. The clinician should also escalate the case when the cytology suggests a neoplastic process. The histopathology is needed to confirm the diagnosis and to determine the treatment plan. The clinician should refer the patient to a specialist for the histopathology and the treatment. ## A Decision Framework for Cytology-Guided Therapy and Recheck Intervals Cytology interpretation becomes clinically useful only when it directly changes a treatment decision or a monitoring plan. A common failure in practice is not the collection or staining of the sample, but the absence of a structured method for translating cytology findings into a specific therapeutic choice and a defined recheck schedule. This section provides a practical decision framework that links cytologic patterns to treatment selection, establishes recheck intervals based on the cellular response, and includes a record system that tracks cytologic changes over time. ### The Cytology-to-Treatment Decision Matrix A decision matrix helps the clinician move from the microscope to the prescription pad in a consistent and defensible manner. The matrix is built on three cytologic questions. First, what organisms are present and in what quantity. Second, what inflammatory cell population predominates. Third, what is the condition of the epithelial cells. The answers to these three questions determine whether the clinician prescribes a topical agent, a systemic agent, or both, and whether the clinician should pursue additional diagnostics. The table below summarizes the most common cytologic patterns and the corresponding initial treatment decisions. This matrix is not a substitute for clinical judgment, but it provides a starting point for a structured approach. | Cytologic Finding | Predominant Cell Type | Initial Treatment Decision | Recheck Interval | |---|---|---|---| | Malassezia yeast, low numbers | Few or no inflammatory cells | Topical antifungal cleansing | 7 to 14 days | | Malassezia yeast, high numbers | Neutrophils | Topical antifungal plus anti-inflammatory | 7 days | | Cocci, intracellular | Neutrophils with toxic change | Topical antibacterial, consider systemic | 7 days | | Cocci, extracellular only | Neutrophils | Topical antibacterial | 7 to 14 days | | Rods | Neutrophils | Systemic antibacterial, culture recommended | 7 days | | Mixed bacteria and yeast | Neutrophils and macrophages | Combination topical therapy | 7 days | | Acantholytic cells | Neutrophils, no bacteria | Consider immune-mediated disease, biopsy | 7 days | | No organisms, no inflammatory cells | Epithelial cells only | Reassess collection technique | 14 days | The matrix is most useful when the clinician records the cytology findings in a standardized format. The presence of a single organism type with a clear inflammatory response supports a straightforward treatment plan. The presence of mixed organisms or a predominance of rods should prompt a more cautious approach and a lower threshold for systemic therapy and culture. The absence of organisms in a lesion that appears infected on physical examination should prompt a reassessment of the collection technique and consideration of a deeper sample. ### Recheck Cytology as a Monitoring Tool The recheck cytology is a distinct procedure from the initial diagnostic cytology. The purpose of the recheck is to assess the response to treatment and to determine whether the treatment should be continued, changed, or stopped. The recheck cytology should be performed at a defined interval after the initiation of treatment. The interval depends on the condition being treated and the expected response time. For bacterial infections, a recheck cytology at 14 days is a reasonable starting point. The cytology should show a reduction in the number of bacteria and a change in the inflammatory cell population. The presence of a large number of neutrophils at the recheck suggests that the infection is not resolving, and the clinician should consider a culture and sensitivity test. The presence of a large number of macrophages suggests that the infection is resolving and that the inflammatory response is transitioning to a reparative phase. For Malassezia infections, a recheck cytology at 7 to 14 days is appropriate. The cytology should show a reduction in the number of yeast cells. The persistence of a high number of yeast cells after treatment suggests that the treatment is not effective or that the underlying cause has not been addressed. The clinician should consider the possibility of a resistant infection or an underlying condition such as allergy or endocrine disease. The recheck cytology is also useful for monitoring the response to treatment in neoplastic conditions. The cytology is not a substitute for histopathology, but it can be used to monitor the response to chemotherapy or radiation therapy. The cytology can show a reduction in the number of neoplastic cells or a change in the cell morphology. The clinician should interpret the cytology in the context of the clinical response and the treatment plan. ### A Standardized Cytology Record System A standardized record system is essential for tracking cytologic findings over time and for communicating the results to other members of the veterinary team. The record should include the patient identification, the date of the sample, the site of the sample, the collection method, and the staining method. The record should also include a description of the cell types and the organisms, and the interpretation of the results. The record should be structured in a way that allows for easy comparison of cytology results over time. A simple table or a standardized form can be used. The form should include the following fields: - Patient name and identification number - Date of the sample - Sample site - Collection method - Staining method - Cell types present - Organisms present - Interpretation - Treatment plan - Recheck interval The record should be completed at the time of the cytology evaluation. The clinician should not rely on memory to record the results. The record is a legal document and should be accurate and complete. The record is also a communication tool that allows other members of the veterinary team to understand the patient's history and the treatment plan. The record system is particularly important for patients with chronic skin or ear disease. These patients may have multiple cytology samples collected over a period of months or years. The record allows the clinician to track the progression of the disease and the response to treatment. The record can also be used to identify patterns that are not apparent from a single cytology evaluation. ### Troubleshooting the Nondiagnostic Sample A nondiagnostic cytology sample is a common problem in practice. The sample may be too thin, too thick, or not representative of the lesion. The clinician should have a systematic approach to troubleshooting the nondiagnostic sample. The first step is to assess the quality of the sample. The sample should be examined under the microscope to determine if the cells are present and if the cells are well preserved. If the sample is too thin, the clinician should collect a new sample. The new sample should be collected from the same site, but the clinician should apply more pressure or use a different collection technique. If the sample is too thick, the clinician should collect a new sample and apply the sample to the slide in a thinner film. The clinician should also consider the possibility that the sample is not representative of the lesion. The clinician should collect a sample from a different area of the lesion or from a different lesion. If the sample is not well preserved, the clinician should consider the possibility that the sample was not stained correctly. The staining time should be adjusted based on the thickness of the smear. The clinician should also consider the possibility that the sample was not fixed correctly. The sample should be fixed in methanol before staining. The clinician should also consider the possibility that the sample is not diagnostic because the lesion is not cellular. This is a common problem with cystic lesions and with lesions that are predominantly fibrous. The clinician should consider a different diagnostic approach, such as a biopsy, if the cytology is not diagnostic. ### Common Failure Patterns in the Decision Framework The decision framework is not a substitute for clinical judgment, and it can fail if the clinician does not follow the framework or if the framework is not appropriate for the clinical situation. The most common failure pattern is the failure to perform a recheck cytology. The clinician may prescribe a treatment and not schedule a recheck. This is a common problem in a busy practice. The recheck cytology is essential for monitoring the response to treatment and for adjusting the treatment plan. Another common failure pattern is the failure to interpret the cytology in the context of the clinical presentation. The cytology is a diagnostic test, but it is not the only diagnostic test. The clinician should consider the history, the physical examination, and the results of other diagnostic tests. The cytology should be interpreted in the context of the clinical presentation. The failure to consider the underlying condition is another common failure pattern. The cytology may show a bacterial infection, but the underlying cause of the infection may be an allergy or an endocrine disease. The clinician should treat the underlying condition in addition to the infection. The failure to address the underlying condition will result in a recurrence of the infection. The failure to escalate the case is a serious failure pattern. The clinician should escalate the case to a specialist when the cytology is not diagnostic, when the patient is not responding to the treatment, or when the cytology suggests a neoplastic process. The specialist can provide a more detailed evaluation and a more advanced diagnostic workup. ### The Role of the Decision Framework in Preventive Care The decision framework is not limited to the treatment of active disease. It can also be used in the context of preventive care. The American Veterinary Medical Association emphasizes the importance of regular veterinary examinations for early disease detection and preventive care. The American Animal Hospital Association similarly supports diagnostic approaches that enhance preventive care and life-stage appropriate medicine. The cytology can be used as a screening tool in the context of a regular examination. The cytology can be used to identify subclinical infections or overgrowths. The early identification of these conditions can prevent the development of more serious disease. The cytology can also be used to monitor the health of the skin and the ear in patients with a history of chronic disease. The World Small Animal Veterinary Association emphasizes the importance of evidence-based clinical guidelines in companion-animal practice. The cytology is a foundational component of dermatologic diagnostic guidelines. The decision framework can be used to guide the frequency of cytology in the context of preventive care. The frequency of the cytology depends on the clinical situation. The cytology is repeated when the patient is not responding to the treatment or when the clinical presentation changes. The clinician should discuss the frequency of the cytology with the client. ### The Role of the Client in the Decision Framework The client is an important part of the decision framework. The client should be informed about the purpose of the cytology and the treatment plan. The client should also be informed about the importance of the recheck cytology. The client should be encouraged to ask questions and to report any changes in the patient's condition. The client should be informed about the limitations of the cytology. The client should understand that the cytology is a diagnostic test that provides information about the cells and the organisms in the sample. The client should understand that the cytology cannot provide a definitive diagnosis of cancer and that a histopathology may be needed. The client should also be informed about the risks of the cytology. The risks are minimal, but the client should be aware of the possibility of bleeding and infection. The client should be informed about the signs of a complication and should be instructed to contact the clinic if a complication occurs. The client should be informed about the cost of the cytology and the recheck cytology. The client should be informed about the cost of the treatment and the cost of the recheck. The client should be informed about the expected duration of the treatment and the expected response to the treatment. ### The Decision Framework in the Context of Referral The decision framework can also be used to determine when to refer a patient to a specialist. The clinician should refer the patient to a specialist when the cytology is not diagnostic, when the patient is not responding to the treatment, or when the cytology suggests a neoplastic process. The specialist can provide a more detailed evaluation and a more advanced diagnostic workup. The referral is also appropriate when the clinician is not comfortable with the interpretation of the cytology. The clinician should refer the patient to a specialist when the clinician is not confident in the diagnosis or the treatment plan. The referral is also appropriate when the patient has a complex medical history or when the patient has a condition that is not responding to the treatment. The referral is also appropriate when the clinician does not have the equipment or the expertise to perform the diagnostic workup. The specialist can provide a more advanced diagnostic workup, including histopathology, culture, and sensitivity testing. The specialist can also provide a more advanced treatment plan, including surgery, chemotherapy, or radiation therapy. The referral should be made in a timely manner. The clinician should not delay the referral if the patient is not responding to the treatment. The referral should be made when the clinician has a concern about the patient's condition. The referral should be made when the clinician has a concern about the diagnosis or the treatment plan. The referral should be made in a way that is respectful of the client and the patient. The clinician should explain the reason for the referral and the expected outcome of the referral. The clinician should provide the specialist with the patient's history, the physical examination findings, and the cytology results. The clinician should also provide the specialist with the treatment plan and the response to the treatment. The referral should be made in a way that is consistent with the guidelines of the World Organisation for Animal Health. The World Organisation for Animal Health provides that the use of diagnostic tests is an important component of animal health and welfare. The referral is a component of the diagnostic workup and the treatment plan. ### The Decision Framework and the Medical Record The decision framework is a component of the medical record. The medical record should include the cytology results, the interpretation of the results, the treatment plan, and the recheck interval. The medical record should also include the client's instructions and the client's response to the instructions. The medical record is a legal document and should be accurate and complete. The medical record should be written in a clear and concise manner. The medical record should be written in a way that is understandable to other members of the veterinary team. The medical record should be written in a way that is understandable to the client. The medical record should be reviewed on a regular basis. The review should be conducted by the veterinarian or by a member of the veterinary team. The review should identify any errors or omissions in the medical record. The review should also identify any opportunities for improvement in the decision framework. The medical record should be used to monitor the quality of the care. The medical record can be used to identify the patterns of care and the outcomes of the care. The medical record can be used to identify the areas where the care can be improved. The medical record can be used to identify the areas where the decision framework can be improved. The medical record should be used to communicate with the client. The medical record should be used to inform the client about the patient's condition and the treatment plan. The medical record should be used to inform the client about the recheck interval and the expected response to the treatment. The medical record should be used to inform the client about the risks and the benefits of the treatment. The medical record should be used to communicate with the specialist. The medical record should be used to provide the specialist with the patient's history, the physical examination findings, and the cytology results. The medical record should be used to provide the specialist with the treatment plan and the response to the treatment. The medical record should be used to provide the specialist with the client's instructions and the client's response to the instructions. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the client's response to the treatment. The medical record should be used to inform the client of the risks and the benefits of the treatment. The medical record should be used to communicate with the veterinary team. The medical record should be used to inform the veterinary team of the patient's condition and the treatment plan. The medical record should be used to inform the veterinary team of the recheck interval and the client's response to the treatment. The medical record should be used to inform the veterinary team of the risks and the benefits of the treatment. The medical record should be used to communicate with the client. The medical record should be used to inform the client of the patient's condition and the treatment plan. The medical record should be used to inform the client of the recheck interval and the ## Frequently Asked Questions ### What is the difference between cytology and histopathology? Cytology evaluates individual cells that are collected from a lesion, while histopathology evaluates a tissue sample that is processed and stained to examine the tissue architecture. Cytology is a rapid and inexpensive test, but it cannot provide the same level of detail as histopathology. Histopathology is the gold standard for the diagnosis of neoplastic conditions. ### How long does it take to get the results of a cytology? The results of a cytology can be obtained in a few minutes if the sample is stained and evaluated in the clinic. The results of a histopathology can take several days to a week, depending on the laboratory. The clinician should discuss the expected turnaround time with the client. ### Can cytology be used to diagnose cancer? Cytology can be used to identify a neoplastic cell population, but it cannot provide a definitive diagnosis of cancer. The cytology can suggest the presence of a neoplasm, but a histopathology is needed to confirm the diagnosis and to provide the information about the tumor type and the surgical margins. ### What is the best way to collect a sample from a skin lesion? The best way to collect a sample from a skin lesion depends on the type of lesion. A direct impression is used for exudative lesions, and a skin scraping is used for superficial lesions. A fine-needle aspiration is used for nodular lesions. The clinician should choose the technique that is most appropriate for the lesion. ### What are the common organisms that are found in ear cytology? The common organisms that are found in ear cytology are Malassezia and bacteria. Malassezia is a yeast that is a common cause of ear disease, and bacteria are a common cause of ear infection. The presence of these organisms is important for the diagnosis and the treatment of the ear disease. ### What is the role of cytology in the diagnosis of autoimmune skin disease? Cytology can be used to identify the presence of acantholytic cells, which are a characteristic finding of pemphigus vulgaris. The presence of these cells is important for the diagnosis of this immune-mediated disease. However, the cytology is not the definitive diagnosis, and a histopathology is needed to confirm the diagnosis. ### How often should cytology be repeated? The frequency of cytology depends on the clinical situation. The cytology is repeated when the patient is not responding to the treatment or when the clinical presentation changes. The clinician should discuss the frequency of the cytology with the client. ### What are the risks of cytology? The risks of cytology are minimal. The procedure is minimally invasive, and the risks are limited to bleeding and infection. The clinician should use appropriate precautions to minimize the risks. ## Related Veterinary Guides - [Cytology for Skin and Ear Infections: Yeast vs Rod vs Cocci Bacteria](/knowledge/veterinary-medicine/at-home-diagnostics/cytology-for-skin-and-ear-infections-yeast-vs-rod-vs-cocci-bacteria) - [Corticosteroid Use in Canine Dermatology: A Practical Approach](/knowledge/veterinary-medicine/clinical-pharmacology/corticosteroid-use-canine-dermatology-practical-approach) - [Dog Ear Infections Treatment](/knowledge/veterinary-medicine/clinical-methods/dog-ear-infections-treatment) - [Dog Ear Infections Home Treatment](/knowledge/veterinary-medicine/clinical-methods/dog-ear-infections-home-treatment) - [Dog Ear Infections Natural Treatment](/knowledge/veterinary-medicine/clinical-methods/dog-ear-infections-natural-treatment) ## References and Further Reading - [Pet Care](https://www.avma.org/resources-tools/pet-owners). American Veterinary Medical Association. - [AAHA Guidelines](https://www.aaha.org/resources). American Animal Hospital Association. - [Global Guidelines](https://wsava.org/global-guidelines). World Small Animal Veterinary Association. - [Merck Veterinary Manual](https://www.merckvetmanual.com/). Merck Veterinary Manual. - [Cornell University College of Veterinary Medicine](https://www.vet.cornell.edu/). Cornell University. - [Animal Health and Welfare](https://www.woah.org/en/what-we-do/animal-health-and-welfare). World Organisation for Animal Health. - [Malassezia dermatitis in dogs and cats.](https://pubmed.ncbi.nlm.nih.gov/38431127). Veterinary journal (London, England : 1997), 2024. - [Malassezia dermatitis and otitis.](https://pubmed.ncbi.nlm.nih.gov/10563001). The Veterinary clinics of North America. Small animal practice, 1999. - [Distinguishing Between Dermatologic Disorders of the Face, Nasal Planum, and Ears: Great Lookalikes in Feline Dermatology.](https://pubmed.ncbi.nlm.nih.gov/32387302). The Veterinary clinics of North America. Small animal practice, 2020. - [The Role of Interleukin-19 in Contact Hypersensitivity.](https://pubmed.ncbi.nlm.nih.gov/29386478). Biological & pharmaceutical bulletin, 2018. - [Immunohistochemical characterization of cutaneous leishmaniasis in cats from Central-west Brazil.](https://pubmed.ncbi.nlm.nih.gov/31303238). Veterinary parasitology, regional studies and reports, 2019. > This article is educational and is not a substitute for veterinary diagnosis or treatment. Contact a veterinarian for advice about an individual animal.