Canine Cutaneous Parasitic Infections: Diagnosis and Management of Skin Parasites in Dogs

Introduction

Cutaneous parasitic infections in dogs represent a diverse group of diseases caused by arthropods, nematodes, protozoa, and oomycetes. These infections often present with pruritus, alopecia, nodular lesions, ulceration, or dermatitis. Accurate diagnosis requires integration of signalment, travel history, physical examination, and laboratory testing including cytology, histopathology, serology, and nucleic acid amplification methods. Management depends on the specific pathogen and may involve topical or systemic antiparasitic drugs, surgical excision, or supportive care. This article provides an exhaustive review of the major canine cutaneous parasitic infections, emphasizing diagnostic approaches and therapeutic strategies based on peer-reviewed literature.

Ectoparasitic Infestations

Mites: Sarcoptes scabiei, Demodex canis, Otodectes cynotis

Sarcoptic mange caused by Sarcoptes scabiei var. canis is a highly contagious, intensely pruritic dermatitis. The female mite burrows into the stratum corneum, depositing eggs. Diagnosis relies on deep skin scrapings, but sensitivity is low; empiric therapy is often justified in suspect cases. A critically appraised topic identified that systemic treatments such as fluralaner and sarolaner are highly effective [1, 105]. A study evaluating a fluralaner-based ectoparasiticide demonstrated efficacy against sarcoptic mange in naturally infested dogs [105]. Demodectic mange caused by Demodex canis typically presents as localized or generalized alopecia and erythema. Diagnosis is confirmed by deep skin scrapings revealing adult mites, nymphs, and eggs. Otodectes cynotis (ear mite) causes otitis externa and cervical pruritus; identification of mites in otic exudate confirms the diagnosis.

Ticks and Tick-Borne Pathogens

Tick infestations are common worldwide. Species include Rhipicephalus sanguineus sensu stricto, Dermacentor spp., Amblyomma spp., and Ixodes spp. Brown dog ticks (R. sanguineus) are vectors for Ehrlichia canis, Babesia canis, and Anaplasma platys [114, 144]. Recent surveillance studies documented R. sanguineus infestations in stray dogs and their role in emerging Rocky Mountain spotted fever [144]. Molecular detection of tick-borne pathogens in dogs is essential for management of co-infections [101, 126, 136]. Acaricide resistance is a growing concern; a first report of voltage-gated sodium channel mutations conferring pyrethroid resistance in R. sanguineus from Brazil highlights the need for resistance monitoring [110]. Management of tick infestations involves application of topical or oral acaricides (e.g., fluralaner, sarolaner). An efficacy study of an afoxolaner and milbemycin oxime combination demonstrated prevention of Babesia canis transmission by Dermacentor reticulatus [122].

Fleas and Myiasis

Flea infestations (Ctenocephalides felis, C. canis) cause flea allergy dermatitis and serve as vectors for Dipylidium caninum and Bartonella henselae [112, 119]. A survey of flea-borne pathogens in Mediterranean and subtropical regions highlighted the heterogeneity of flea species and the importance of year-round control [112, 119]. Cutaneous myiasis occurs when fly larvae infest wounds or intact skin. Furuncular myiasis caused by Dermatobia hominis is common in Latin America; a study demonstrated effectiveness of sarolaner in clinical management [150]. Auricular myiasis due to Chrysomya bezziana has been reported in Singapore [146]. Myiasis risk factors include poor hygiene and open wounds [78, 135]. Diagnosis involves larval identification and removal.

Cutaneous Larva Migrans

Cutaneous larva migrans (CLM) in dogs is caused by penetration of skin by third-stage larvae of hookworms, primarily Ancylostoma braziliense and Ancylostoma caninum [2, 3, 72, 79, 95]. The larvae migrate within the epidermis, causing serpiginous, erythematous, pruritic tracts. Although CLM is more commonly described in humans, dogs can serve as definitive hosts for A. caninum and as aberrant hosts. A study confirmed A. caninum in dogs in Central Europe, suggesting epidemiological relevance [4]. Diagnosis is clinical, supported by history of exposure to contaminated soil. Molecular identification of Ancylostoma species from fecal samples is possible [5, 79]. Multiple anthelmintic resistance in A. caninum has been documented, necessitating susceptibility testing and drug rotation [6]. Treatment of CLM in dogs involves administration of macrocyclic lactones such as ivermectin or milbemycin oxime; refractory cases have been described [120].

Protozoal Infections: Leishmaniasis

Canine leishmaniasis is caused by Leishmania infantum (syn. L. chagasi) and occasionally Leishmania tropica or Leishmania braziliensis [7, 8, 74, 96]. Sand fly vectors (Phlebotomus spp., Lutzomyia spp.) transmit promastigotes during blood feeding. Amastigotes proliferate within macrophages, leading to visceral and cutaneous manifestations. Cutaneous lesions include alopecia, exfoliative dermatitis, ulceration, and nodular dermatitis [9, 10]. A study of ischemic dermatopathy in dogs with leishmaniosis identified clinical and immunological patterns [11]. Diagnosis is multimodal: serology (ELISA, immunofluorescence), molecular detection (qPCR, LAMP), and cytology/histopathology of skin or lymph node aspirates [12, 13, 14, 64, 67]. A qPCR-based strategy allows differential diagnosis of visceral and cutaneous forms [13]. A systematic review confirmed high accuracy of qPCR for both forms [15]. Recombinant antigens such as Lbk39 and cysteine proteinase B improve serodiagnosis [16, 99]. Loop-mediated isothermal amplification (LAMP) provides a rapid field-deployable option [67]. New rapid diagnostic tests based on chimeric proteins show promise [12].

Treatment of canine leishmaniasis involves meglumine antimoniate combined with allopurinol [17, 140]. Topical therapies including hederagenin saponins and silver nanoparticle biomembranes have been investigated [18, 66]. Owner-administered injections of meglumine antimoniate are feasible [140]. Relapses are common; risk factors include incomplete treatment and high parasite load [138]. Prognostic indicators from a two-decade dataset help guide management [111].

Oomycete Infections: Pythiosis

Pythiosis in dogs is caused by Pythium insidiosum, an aquatic oomycete that causes cutaneous and gastrointestinal lesions. Cutaneous pythiosis presents as ulcerated, granulomatous masses often on the extremities, tail, or perineum [19, 10, 20, 21]. The organism thrives in stagnant water; infection occurs via percutaneous inoculation of zoospores. Diagnosis is based on histopathology (eosinophilic granulomas with hyphae), culture, and PCR. A serum ELISA and PCR combination improves noninvasive diagnosis [22]. Computed tomographic characteristics have been described for noncutaneous forms [10]. Medical treatment alone is often ineffective; surgical excision is the treatment of choice. Antifungals such as amorolfine and azithromycin show in vitro activity, but clinical cure requires complete surgical removal [85]. A retrospective study from northeastern Brazil documented outcomes in domestic animals [21].

Filarioid Nematode Infections

Onchocerca lupi

Onchocerca lupi is a filarial nematode that causes ocular and cutaneous nodules in dogs. It is endemic in the southwestern United States and parts of Europe [23]. Adult worms reside in the periorbital connective tissue, inducing granulomatous inflammation. Diagnosis is by visualization of microfilariae in skin snips or by PCR [23, 82]. A duplex real-time PCR assay differentiates O. lupi from O. volvulus [82]. Treatment includes surgical removal of nodules and administration of macrocyclic lactones; ivermectin may reduce microfilariae.

Cercopithifilaria spp.

Cercopithifilaria bainae and related species are filarioids that inhabit the subcutaneous tissue of dogs. They are transmitted by hard ticks. Clinical signs include papules, nodules, and alopecia, often in the scapular region [24, 84]. Diagnosis is by skin biopsy revealing microfilariae. A case report described a giant cutaneous cyst caused by C. bainae [84]. These filarioids are more prevalent than previously recognized [24].

Other Parasitic Skin Conditions

Trichinellosis

Cutaneous involvement in canine trichinellosis is rare. A case of Trichinella britovi infection in a hunting dog was diagnosed via cutaneous abdominal biopsy, highlighting the utility of muscle biopsy for detection of encysted larvae [25].

Protothecosis

Disseminated protothecosis caused by Prototheca spp. (achlorophyllous algae) can present with cutaneous nodules, although it often involves other organs. A case of disseminated protothecosis co-infected with Hepatozoon canis and Ehrlichia canis was reported [26].

Strongyloidiasis

Strongyloides stercoralis can cause perianal dermatitis in dogs, with migrating filariform larvae in the skin. Molecular characterization of strains in Latin America revealed clinical connections [65]. A clinical review highlighted diagnostic challenges using conventional coprology [27].

Giardiasis and Urticaria

A case of generalized cutaneous urticaria was attributed to Giardia infection in a puppy, suggesting a hypersensitivity reaction to intestinal parasites [70].

Diagnostic Algorithm

A systematic approach to diagnosis of canine cutaneous parasitic infections is presented in the following flowchart.

graph TD
    A[Pruritus, alopecia, nodules, ulcers] --> B{History and physical exam}
    B --> C[Deep skin scraping / hair pluck]
    C --> D{Mites?}
    D -->|Sarcoptes/Demodex| E[Microscopic identification]
    D -->|Negative| F[Consider other causes]
    F --> G[Fecal flotation / Baermann]
    G --> H{Hookworm eggs?}
    H -->|Yes| I[Cytology for CLM?]
    H -->|No| J[Serology for Leishmania]
    J --> K{Positive?}
    K -->|Yes| L[qPCR / LAMP for Leishmania species]
    K -->|No| M[Biopsy / histopathology with special stains]
    M --> N{Granulomatous with hyphae?}
    N -->|Yes| O[Pythium culture / PCR]
    N -->|No| P[PCR for filarioids / Onchocerca]
    P --> Q[Treatment based on etiology]
    I --> Q
    L --> Q
    O --> Q
    E --> Q
    Q --> R[Recheck response, consider drug resistance]

Conclusion

Canine cutaneous parasitic infections encompass a wide etiological spectrum requiring a systematic diagnostic approach. Advances in molecular diagnostics including qPCR, LAMP, and next-generation sequencing have improved species identification and detection of drug resistance. Management strategies must be tailored to the specific pathogen, with consideration of regional epidemiology, co-infections, and resistance patterns. Continued surveillance and One Health perspectives are essential for effective control.

References

[1] Dumitrache MO, Cadiergues MC. The most effective systemic treatment in dogs with sarcoptic mange: a critically appraised topic. BMC Vet Res. 2023. PMID: 37798627.

[2] Bloomquist RF, Elston DM. What's eating you? Hookworm and cutaneous larva migrans. Cutis. 2024. PMID: 39787302.

[3] Coello Peralta RD, Pazmiño Gómez BJ, Salazar Mazamba ML et al. Ecoepidemiology of Ancylostoma spp. in urban-marginal and rural sectors of the Ecuadorian coast and prevalence of cutaneous larvae migrans. Med Sci Monit. 2024. PMID: 38500436.

[4] Liptáková M, Schreiberová A, Cellengová Z et al. The canine hookworm Ancylostoma caninum: first confirmed evidence in a dog in Central Europe: epidemiological relevance or coincidence? Pathogens. 2025. PMID: 41471196.

[5] Coello Peralta RD, Andrada AR, Vinueza RL et al. Identification of Ancylostoma caninum in domestic dogs from Ecuador via various techniques. Med Sci Monit. 2025. PMID: 39754349.

[6] Geary TG, Drake J, Gilleard JS et al. Multiple anthelmintic drug resistance in the canine hookworm Ancylostoma caninum: AAVP position paper and research needs. Vet Parasitol. 2025. PMID: 40596793.

[7] Akhtardanesh B, Sadr S, Khedri J et al. Canine leishmaniasis caused by Leishmania tropica in southeastern Iran: a case series study. Sci Rep. 2024. PMID: 39465272.

[8] Maurelli MP, Zribi L, Fayala NEHB et al. First detection of Leishmania major in dogs living in an endemic area of zoonotic cutaneous leishmaniasis in Tunisia. Parasit Vectors. 2024. PMID: 39123245.

[9] Baneth G, Peri Markovich M, Nachum-Biala Y et al. Retrospective study of canine leishmaniosis in Israel. Parasit Vectors. 2025. PMID: 40615842.

[10] Hamlin AN, Locker S, Huguet E et al. Computed tomographic characteristics of confirmed and presumed noncutaneous pythiosis in 25 dogs. Vet Radiol Ultrasound. 2024. PMID: 38192159.

[11] García N, Cobos À, Solano-Gallego L et al. Clinical, immunological and pathological characteristics of ischemic dermatopathy in dogs with leishmaniosis. Pathogens. 2025. PMID: 40137731.

[12] Dos Santos WJT, Nadaes NR, Dutra AKO et al. Evaluation of a new rapid diagnostic test, based on the chimeric protein Q5, for the diagnosis of human and canine forms of visceral leishmaniasis. Mem Inst Oswaldo Cruz. 2026. PMID: 42207130.

[13] Rihs JB, Vilela MT, Coelho Dos Santos JS et al. A qPCR-based strategy for differential diagnosis of visceral and cutaneous leishmaniasis in humans and dogs. Acta Trop. 2026. PMID: 41610969.

[14] Bento MF, Souza GS, Vieira BS et al. Sensitivity of PCR in conjunctival swab samples for the diagnosis of canine visceral leishmaniasis: a systematic review and meta-analysis. Rev Bras Parasitol Vet. 2023. PMID: 38018627.

[15] Rihs JB, Vilela MT, Dos Santos JSC et al. qPCR as a tool for the diagnosis of visceral and cutaneous leishmaniasis: a systematic review and meta-analysis. Acta Parasitol. 2025. PMID: 39777570.

[16] Manrique-Guzmán YC, Marcolino-Junior LH, Bergamini MF et al. Electrochemical immunosensor construction using Lbk39 recombinant protein for leishmaniasis diagnosis. Int J Biol Macromol. 2025. PMID: 40505915.

[17] Platenik M, Di Loria A, Archer L et al. Evaluation of the cutaneous immunological milieu before and after treatment with meglumine antimoniate in dogs naturally affected by leishmaniosis due to Leishmania infantum. Vet Dermatol. 2026. PMID: 41705575.

[18] Batista DDCS, de Oliveira MR, de Jesus JV et al. Effectiveness of Aloe vera (L.) Burm.F. biomembranes with silver nanoparticles in the clinical experimental treatment of skin lesions of dogs with leishmaniasis. Microb Pathog. 2025. PMID: 40446971.

[19] Cridge H. Pythiosis in dogs. Vet Clin North Am Small Anim Pract. 2025. PMID: 39725575.

[20] Peano A, Min ARM, Fondati A et al. Cutaneous pythiosis in 2 dogs, Italy. Emerg Infect Dis. 2023. PMID: 37347828.

[21] de Souto EPF, Kommers GD, Souza AP et al. A retrospective study of pythiosis in domestic animals in

[22] Barua S, Tarannum A, Newton J et al. Improving noninvasive diagnosis of cutaneous and gastrointestinal forms of Pythium insidiosum infections in dogs: complementary roles of serum-based ELISA and polymerase chain reaction. Am J Vet Res. 2026. PMID: 41135573.

[23] Kelly MA, Clarke E, Hakimi H et al. Prevalence of Onchocerca lupi in shelter dogs from an endemic region of the Southwestern USA. Parasit Vectors. 2025. PMID: 40764591.

[24] Bezerra-Santos MA, Dantas-Torres F, Ramos RAN et al. Cercopithifilaria spp. of dogs: little known but prevalent filarioids beneath the skin. Parasit Vectors. 2023. PMID: 37880799.

[25] Basso W, Moré G, Pischon H et al. Cutaneous abdominal biopsy enabled the diagnosis of clinical Trichinella britovi infection in a hunting dog. Vet Parasitol. 2025. PMID: 40043332.

[26] Aicardi L, Ballesteros MA, Cuestas ML et al. Disseminated protothecosis in a dog coinfected with Hepatozoon canis and Ehrlichia canis. Vet Res Commun. 2025. PMID: 39841276.

[27] Colella A, Buonfrate D, Lo Tempio F et al. Clinical insights to address canine strongyloidosis in daily practice. Top Companion Anim Med. 2024. PMID: 38184143.

[28] Archbold K, Pineda V, Calzada JE et al. Using Bayesian methods to evaluate the diagnostic performance of blood-based diagnostic tests for American cutaneous leishmaniasis and Chagas disease in rural Panamanian dogs in the absence of a gold standard. Vet Parasitol. 2026. PMID: 41962193.

[29] Murillo A, Lebrero ME, Valdés M et al. Post-surgical seroreversion in a case of equine cutaneous leishmaniosis by Leishmania infantum. Vet Res Commun. 2026. PMID: 41504811.

[30] Escobar ST, Petronic-Rosic V. Clinical, histopathologic, and immunohistochemical patterns of cutaneous leishmaniasis. Clin Dermatol. 2025. PMID: 41043653.

[31] Baghad B, Mouhsine Z, Chekairi FZ et al. New epidemio-clinical insights into cutaneous leishmaniasis caused by Leishmania infantum in Casablanca, Morocco. Infect Dis Now. 2025. PMID: 40615082.

[32] Villanueva-Saz S, Marteles D, Ortuñez Á et al. Absence of specific humoral response in three dogs with clinical leishmaniosis. Acta Vet Scand. 2025. PMID: 40484952.

[33] Son KY, Park GG, Song JH. Imported case of canine viscerocutaneous leishmaniasis in South Korea: clinical presentation and diagnostic approach in a Labrador Retriever. J Vet Sci. 2025. PMID: 40461426.

[34] Lazo-Láscarez S, Alvarado-Hidalgo I, Rojas-Araya D et al. Canine intestinal pseudomyiasis by blow flies and first documented case report caused by Lucilia cuprina in Central America. Parasitol Int. 2025. PMID: 40345641.

[35] Marcili A, Sousa IKF, Sousa RDS et al. Occurrence of Leishmania infantum in horses from Brazilian Amazon. Vector Borne Zoonotic Dis. 2025. PMID: 40314088.

[36] Güler E, Özbilgin A, Çavuş İ et al. [Molecular characterization of cutaneous leishmaniasis and canine leishmaniasis strains isolated from Northern Cyprus and their clinical reflections in mice models]. Mikrobiyol Bul. 2025. PMID: 40277267.

[37] Freire LC, Costa SS, Tedeschi ALF et al. Synthetic peptides derived from hypothetical proteins as potential antigens for the diagnosis of canine visceral leishmaniasis and tegumentary leishmaniasis. Exp Parasitol. 2025. PMID: 39921056.

[38] de Luna RLN, Sales KGDS, Bonifácio LLN et al. Rapid isothermal molecular tests to discriminate between Leishmania braziliensis and Leishmania infantum infections in dogs. Parasit Vectors. 2025. PMID: 39773298.

[39] Suschinel R, Jaimes-Mogollón AL, Sim SF et al. Identification of putative volatile biomarkers of canine leishmaniasis in dog's breath and hair employing a novel algorithm for automated chromatographic peak detection and matching. Anal Bioanal Chem. 2025. PMID: 39722103.

[40] Stoimenov G, Tchakarova S. Clinical manifestations and diagnostic approaches in cases of canine leishmaniasis in Bulgaria. Vet Ital. 2024. PMID: 38898792.

[41] Klein PA, Parisi R, Daniel JM et al. Dermatologic manifestations of zoonotic diseases transmitted by dogs: "Spot" could give you spots. Int J Dermatol. 2024. PMID: 38845109.

[42] Calvo-Sánchez N, Gómez Á, Pérez E et al. A case report of acute claudication due to vena cava thromboembolism in a dog naturally infected with Leishmania infantum. Vet Res Commun. 2024. PMID: 38630425.

[43] Bennani H, Raiteb M, Mezouari EE et al. Cutaneous larva migrans. Clin Lab. 2024. PMID: 38623662.

[44] Behniafar H, Taghipour N, Spotin A et al. Detection and phylogenetic analysis of kinetoplast DNA of Leishmania infantum infected humans, domestic dogs and sandflies in Northwest Iran. PLoS One. 2024. PMID: 38478521.

[45] Thomsen AS, Petersen MP, Willesen JL et al. Clinical bleeding diathesis, laboratory haemostatic aberrations and survival in dogs infected with Angiostrongylus vasorum: 180 cases (2005-2019). J Small Anim Pract. 2024. PMID: 38332620.

[46] Shrestha A, K C K, Baral A et al. Cutaneous larva migrans in a child: a case report and review of literature. Ann Med Surg (Lond). 2024. PMID: 38222776.

[47] Kuna A, Olszański R, Sikorska K. Cutaneous larva migrans as a frequent problem in travellers. Int Marit Health. 2023. PMID: 38111246.

[48] Patiño LH, Ballesteros N, Muñoz M et al. Validation of Oxford nanopore sequencing for improved New World Leishmania species identification via analysis of 70-kDA heat shock protein. Parasit Vectors. 2023. PMID: 38111024.

[49] Rasheed SB, Shah MZ, Jamal Q. Molecular identification of Leishmania tropica in mammals occurring in human-inhabited areas of a cutaneous leishmaniasis endemic focus in North-West Pakistan. Parasitol Res. 2023. PMID: 38052938.

[50] Veras PST, de Santana MBR, Brodskyn CI et al. Elucidating the role played by bone marrow in visceral leishmaniasis. Front Cell Infect Microbiol. 2023. PMID: 37860064.

[51] Zribi L, El Houda Ben-Fayala N, Aissi W et al. Canine Leishmania spp. infection in two distinct foci of visceral and cutaneous leishmaniasis in Tunisia. Vet Parasitol Reg Stud Reports. 2023. PMID: 37652625.

[52] Santos Zanini M, Ataíde Siqueira L, Vieira Almeida Y et al. Treatment of canine cutaneous leishmaniasis by Leishmania (Viannia) braziliensis in dogs with furazolidone and β-cyclodextrin: case report. Vet Ital. 2022. PMID: 37219838.

[53] de Pinho FA, Mendes MO, de Magalhães VLP et al. Clinical evolution of equine leishmaniasis with self-limiting cutaneous disease caused by Leishmania infantum in northeastern Brazil: a case report. Vet Parasitol Reg Stud Reports. 2023. PMID: 37208087.

[54] Pagniez J, Petitdidier E, Parra-Zuleta O et al. A systematic review of peptide-based serological tests for the diagnosis of leishmaniasis. Parasite. 2023. PMID: 37010451.

[55] Segura GBR, Ochoa WHS, Matta VLRD et al. Can domestic dogs be considered a good reservoir of Leishmania (L.) infantum chagasi in an endemic area of nonulcerated cutaneous leishmaniasis in Southern Honduras? Rev Inst Med Trop Sao Paulo. 2023. PMID: 36995877.

[56] Ludolf F, Ramos FF, Coelho EAF. Immunoproteomics and phage display in the context of leishmaniasis complexity. Front Immunol. 2023. PMID: 36845148.

[57] Silva CJD, Monteiro JFDCLS, Lima KPB et al. Study on the zoonotic cycle of tegumentary leishmaniasis in an endemic area of a metropolitan region in the Northeastern region of Brazil. Rev Inst Med Trop Sao Paulo. 2022. PMID: 36197421.

[58] Galán-Relaño Á, Maldonado A, Gómez-Gascón L et al. Pre-test probability and likelihood ratios for clinical findings in canine leishmaniasis. Transbound Emerg Dis. 2022. PMID: 36183344.

[59] Silva CJD, Lima KPB, Monteiro JFDCLS et al. Leishmania V. braziliensis infection in asymptomatic domestic animals within an endemic region in the Northeast of Brazil. Rev Soc Bras Med Trop. 2022. PMID: 35976338.

Disclaimer: This article is for educational and informational purposes only. It is not intended to substitute for professional veterinary advice, diagnosis, treatment, or regulatory guidance. Always consult a licensed veterinarian or qualified specialist regarding animal health, disease diagnosis, and therapeutic decisions.