Hot Spots on Dogs: Causes, Symptoms, and Where They Appear

Name: Hot Spots on Dogs: Causes, Symptoms, and Where They Appear
Creator: Dr. Zubair Khalid

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-10-02

Hot spots on dogs are raw, weeping patches of skin that appear fast, often within hours. What causes dog hot spots is usually a mix of an underlying trigger (allergies, fleas, moisture trapped in the coat, or an ear or anal gland problem) plus the dog's own licking and chewing, which makes the damage worse. The good news is that most hot spots are treatable, and they do not spread to people or other pets.

This article is educational and is not a substitute for veterinary diagnosis or treatment.

Quick Answer

A hot spot is a fast-growing, red, moist, hairless sore that is warm to the touch and often oozes [1].
The most common triggers are allergies and external parasites such as fleas, plus moisture trapped against the skin in thick or matted coats [1].
Ear infections and anal gland infections can start a cycle of licking and chewing that creates a hot spot [1].
Hot spots are not contagious to other pets or to people. The bacteria involved come from the dog's own skin.
If the spot is growing, very painful, or your dog seems sick, call your veterinarian. Small, early spots sometimes respond to home care, but many need prescription treatment.

What Is a Hot Spot, in Plain Words

"Hot spot" is the everyday name for a condition veterinarians call moist dermatitis or pyotraumatic dermatitis. The name comes from the heat that inflammation generates in the skin [1]. The skin's response to any insult, whether an irritant, an allergen, a parasite, or an infection, shows up as redness, itching, scaling, odor, oiliness, and hair loss [2]. A hot spot is that reaction concentrated into one angry, self-perpetuating patch.

The "pyotraumatic" part means pus plus self-trauma. Your dog feels an itch or a sting, licks or chews at it, and the licking damages the skin further. That damage itches more, so your dog licks more. The cycle can turn a small itch into a quarter-sized raw wound in a single afternoon.

Hot spots are most common in dogs with long or thick coats, such as Newfoundlands, German Shepherd Dogs, and Golden Retrievers [1]. Dogs with drop ears or heavy coats are also at higher risk [1]. Warm weather brings more cases, but hot spots can happen any time of year [1].

Hot Spots in Dogs Symptoms: What You Will Notice

The signs are usually hard to miss once you part the hair.

A sharply defined, red, moist, hairless patch
Oozing serum or pus, sometimes with a yellow crust
A bad or yeasty smell from the area
Heat coming off the skin, which is where the name comes from [1]
Constant licking, chewing, scratching, or rubbing at one spot
Whining or pulling away when you touch the area
Matted or clumped hair over and around the sore

Some dogs seem mildly annoyed. Others are clearly uncomfortable and cannot settle. The speed of onset is one of the most telling features. A hot spot can go from normal skin to a raw, oozing sore in hours, which is much faster than most other skin problems.

Where Hot Spots Appear

Location often points to the trigger.

Under the ear: often linked to ear infections, especially in drop-eared dogs and dogs who swim [1].
The belly and groin: common in dogs with environmental or food allergies, since these areas have thin hair and lots of skin-to-skin contact. See our guide to hot spots on dogs belly for more detail.
The paws: interdigital dermatitis is a significant problem in dogs with atopic dermatitis, and the moist spaces between the toes hold heat and bacteria [3]. Our article on hot spots in dogs paws walks through what to look for.
The tail base and rump: frequently tied to fleas and anal gland discomfort [1]. Read more in dog hot spot on tail.
The face and cheeks: often seen in dogs who scratch at their ears or have facial fold moisture. See dog hot spot on face.
Anywhere under a mat: matted hair traps moisture against the skin and sets up infection and sores [1].

Hot Spots vs. Other Skin Problems

Feature	Hot Spot	Superficial Pyoderma	Pemphigus Foliaceus
Onset	Very fast, hours to a day	Gradual, days to weeks	Gradual to moderate
Appearance	Moist, oozing, hairless, sharply defined	Papules, pustules, yellow crusts, collarettes [4]	Crusts, scales, often on the face and paw pads
Main symptom	Intense itching and pain at one site	Itching, odor, hair loss	Crusting, sometimes painful
Typical trigger	Allergies, moisture, fleas, ear or anal gland disease [1]	Often secondary to atopic dermatitis [4]	Autoimmune
Contagious?	No	No	No

Superficial pyoderma is a common bacterial skin infection in dogs with atopic dermatitis, and it can look similar to a hot spot at first glance [4]. Pemphigus foliaceus is an autoimmune disease that can mimic pyoderma, which is why veterinarians sometimes use cytology (looking at cells under a microscope) to tell them apart [5]. If the lesion does not respond to standard treatment, your veterinarian may want to look deeper.

What Causes Dog Hot Spots

There is rarely one single cause. Most hot spots are the end result of a trigger plus self-trauma.

Allergies

Allergies are a primary cause [1]. Dogs with atopic dermatitis are especially prone to pyotraumatic dermatitis, and the severity can depend on how long the lesion has been present, how large it is, and whether bacteria have moved in [6]. Food allergies and flea allergy dermatitis can do the same thing.

Moisture and Coat Type

A dog who swims, wades, or even just stands in a warm summer rain is prone to hot spots if the coat does not dry fully [1]. Matted areas hold moisture against the skin and raise the risk of infection and sores [1]. Thick, double, or long coats dry slowly, which is why these breeds top the list [1].

External Parasites

Fleas are a primary cause [1]. Any parasite that causes itching, including fleas and mites, can start the lick-chew cycle.

Ear Infections

Ear infections, often from water in the ears after swimming, can lead to hot spots under the ear [1]. Drop-eared dogs are at higher risk [1].

Anal Gland Disease

Anal gland infections can stimulate licking and chewing at the rear end, which produces hot spots [1]. The initial sore can be easy to miss if you do not look under your dog's furry tail [1].

Other Contributors

Any source of skin inflammation can set the stage, including irritants, burns, trauma, and bacterial, viral, parasitic, or fungal infection [2]. Dermatitis can also be tied to internal or body-wide disease [2].

Hot Spots in Dogs Contagious? What You Need to Know

No. Hot spots are not contagious to other pets or to people. The bacteria that colonize a hot spot normally live on your dog's skin. The problem is that the skin barrier has broken down, not that your dog caught something from another animal. You do not need to isolate your dog, and you do not need to worry about catching it yourself. If more than one pet in the house has skin issues, that usually points to a shared environmental trigger such as fleas or allergens, not to a contagious hot spot.

How Veterinarians Diagnose Hot Spots

Most hot spots are diagnosed by history and physical exam. Your veterinarian will ask when the sore appeared, whether your dog has been swimming or scratching, and whether there have been skin problems before.

The exam focuses on the lesion itself and on finding the trigger. Your veterinarian will look in the ears, check the anal glands, and comb through the coat for fleas, flea dirt, and mats [1]. They may clip the hair around the sore so they can see the full extent of the damage and keep the area dry.

If the lesion looks unusual, is not improving, or keeps coming back, further testing may help. Cytology (impression smears) can identify bacteria and help distinguish pyoderma from autoimmune disease such as pemphigus foliaceus [5]. Blood markers of inflammation are being studied in dogs with pyoderma, but they are not yet a routine diagnostic tool [7].

Treatment Options

Treatment depends on how big the lesion is, how deep it goes, and what started it.

Clipping and Cleaning

Clipping the hair around the sore is often the first step. It removes the matted, moist coat that feeds the problem and lets the skin dry [1]. Your veterinarian will clean the area with an appropriate antiseptic.

Topical Therapy

Medicated shampoos, sprays, creams, and wipes are common. Which product and how often depends on the depth of the infection and your dog's skin. Follow your veterinarian's instructions exactly, since some human products are irritating or toxic to dogs.

Systemic Treatment

Antibiotics are used when there is a bacterial infection, and antipruritic (anti-itch) medication helps break the lick-chew cycle. Your veterinarian calculates the dose from your dog's weight and health, so never use leftover medication from a previous visit or medication prescribed for another pet.

Treating the Underlying Trigger

This is the part that prevents recurrence. Ear infections, anal gland disease, fleas, and allergies all need their own treatment plan [1]. If allergies are the driver, long-term management may include allergy medication, prescription diets, or immunotherapy.

Newer Options

A 2025 case series described eight dogs with acute pyotraumatic dermatitis who were treated with fluorescent light energy alone. All lesions resolved within a maximum of two weekly sessions, and none of the dogs had recurrence in the treated area during at least one month of follow-up [6]. This is a small, early report, so ask your veterinarian whether it fits your dog's situation. Focal cryotherapy has also been studied for interdigital itching in dogs with atopic dermatitis, with improvement in redness and severity scores after treatment [3].

Home Care for Small, Early Spots

If the spot is small, your dog is comfortable, and you caught it early, your veterinarian may guide you through home care. That usually means keeping the area clean and dry, preventing licking with an Elizabethan collar or similar device, and applying whatever topical product your veterinarian recommends. Do not apply human antibiotic ointments, steroid creams, or home remedies without asking first.

Recovery, Outlook, and Long-Term Management

Most uncomplicated hot spots improve within days once treatment starts, and many resolve within one to two weeks. The hair usually grows back, though it can take weeks to months for the coat to look normal again.

The bigger question is whether it will come back. If the underlying trigger is not addressed, recurrence is common. Dogs with allergies tend to have repeated episodes, and the severity of pyotraumatic dermatitis in allergic dogs can vary with how quickly treatment starts and whether bacteria are involved [6].

Long-term management usually means:

Keeping allergies under control with your veterinarian's plan
Staying on year-round flea prevention
Checking and drying the ears after swimming
Keeping the coat clipped short or well-groomed in at-risk breeds
Checking the tail base and anal gland area regularly [1]

Prevention

You cannot prevent every hot spot, but you can lower the odds.

Dry your dog thoroughly after swimming, bathing, or rain, especially in thick-coated breeds [1].
Prevent and treat mats. Matted hair holds moisture against the skin [1].
Stay current on flea control, since fleas are a primary cause [1].
Treat ear infections promptly, particularly in drop-eared dogs [1].
Have anal glands checked if your dog scoots or licks at the rear end [1].
Manage allergies with your veterinarian instead of waiting for flare-ups.
Do a quick weekly skin check. Part the coat, look at the belly, paws, ears, and tail base, and feel for warm or damp spots. Catching a hot spot early can save your dog discomfort and save you a veterinary bill [1].

Limitations and When to Contact a Veterinarian

This article covers general information. Your dog's individual case needs a veterinarian who can examine the skin, find the trigger, and prescribe the right treatment.

Contact your veterinarian the same day if:

The sore is growing quickly or is larger than a quarter
Your dog is in obvious pain or will not let you near the area
The lesion is on the face, near the eye, or in the ear canal
Your dog is licking so much that the skin is bleeding
You see pus, a foul smell, or spreading redness

Seek emergency care now if:

Your dog is lethargic, vomiting, or has a fever
The swelling spreads rapidly or the skin looks black or dead
Your dog seems systemically ill, not just itchy

Schedule a routine visit if:

The spot is small and stable but not improving after a day or two of home care
Hot spots keep coming back
Your dog has other signs such as ear odor, head shaking, scooting, or hair loss elsewhere

If you are unsure whether a lesion is a hot spot or something else, our visual guide to dog hot spot or something worse can help you decide how urgently to call.

Frequently Asked Questions

Do hot spots spread to other dogs or to people?

No. Hot spots are not contagious. The infection comes from bacteria that normally live on your dog's skin, and it flares when the skin barrier breaks down. If other pets in the home have skin problems, look for a shared cause such as fleas or allergies.

How fast can a hot spot appear?

Very fast. A hot spot can go from normal skin to a raw, oozing sore in a matter of hours. That speed is one of the main features that separates a hot spot from other skin conditions.

Can I treat a hot spot at home?

Sometimes, if it is small and your dog is comfortable. Keep the area clean and dry, stop your dog from licking it, and use only products your veterinarian recommends. If the spot is growing, painful, or smelly, it needs veterinary care.

Why does my dog keep getting hot spots?

Recurring hot spots usually mean the underlying trigger was never fixed. Allergies, fleas, ear infections, and anal gland disease are common culprits. Your veterinarian can help you build a plan that addresses the cause, not just the sore.

Are certain breeds more likely to get hot spots?

Yes. Dogs with long or thick coats, such as Newfoundlands, German Shepherd Dogs, and Golden Retrievers, are most commonly affected. Dogs with drop ears or heavy coats are also at higher risk.

References

Hot spots. Cornell University College of Veterinary Medicine.
Dermatitis and Dermatologic Problems in Dogs - Dog Owners. Merck Veterinary Manual.
Effect of localized cryotherapy on interdigital pruritus of dogs with canine atopic dermatitis. Journal of veterinary science, 2025.
Standardising Assessment of Superficial Pyoderma in Dogs: Proposal of a Severity Score. Veterinary dermatology, 2026.
Comparison of selected cytomorphological features of canine pemphigus foliaceus and superficial pyoderma. Veterinary dermatology, 2024.
Photobiomodulation with fluorescent light energy as a sole treatment of pyotraumatic dermatitis (hot spot): a case series. Journal of the American Veterinary Medical Association, 2025.
Investigations of Procalcitonin, Interleukin-8 and Defensin-β in Dogs with Superficial and Deep Pyoderma. Veterinary sciences, 2026.