Hot Spots on Dogs: What Causes Them and How to Treat Them

A hot spot can appear in an afternoon. One minute your dog is scratching a spot on its hip, and a few hours later there's a raw, wet, angry patch the size of a coin. By the next morning it might be the size of your palm.

The good news is that hot spots are very treatable. The trick is to stop the cycle that creates them, and to work out what started the itch in the first place. Otherwise, you'll be back at the vet in a month.

What is a hot spot?

A hot spot is the common name for acute moist dermatitis, also called pyotraumatic dermatitis. It's a patch of skin that has been damaged by licking, chewing or scratching and then infected by bacteria that normally live on the skin. Vets class it as a surface skin infection.

Think of a scraped knee that you keep picking. Each pick reopens it, and it never gets the chance to scab over. A hot spot works the same way, except your dog can't stop itself. The more it licks, the more it itches. This is often called the lick-itch-lick cycle.

What does a hot spot look like?

A hot spot is easy to spot once you know what to look for. It's usually:

• Red, raw and moist, sometimes oozing clear fluid or pus
• Hairless, or with matted fur stuck down by the discharge
• Hot and painful to touch
• Well defined, often round or oval
• Smelly if the infection is established

Hot spots favor the head, ears, cheeks, hips, base of the tail and the legs. Thick-coated dogs hide them well. A hot spot can sit under a mat of wet fur for days before you notice. Part the coat and look if your dog keeps licking one place.

What causes hot spots on dogs?

Dogs don't get hot spots out of nowhere. Something always starts the itch. Common triggers include the following.

Allergies and fleas

Flea allergy is the classic cause. A dog that's allergic to flea saliva reacts to a single bite, and the itch centers on the lower back, tail base and rear thighs. Environmental allergies (pollen, dust mites) and food allergies also cause itching that leads to hot spots, especially on the paws, face and flanks. Golden Retrievers, Labrador Retrievers and German Shepherds get them often.

Moisture and matted fur

Damp fur traps bacteria against the skin. Dogs that swim, get bathed without being dried properly or live in humid climates are at risk, especially thick-coated breeds like Newfoundlands, Saint Bernards and Golden Retrievers. Hot spots in summer often follow a lake swim, with a patch hiding under a damp, matted coat.

Pain, ear and anal gland problems

A dog with an ear infection scratches behind the ear and cheek. A dog with sore anal glands licks its rear. A dog with arthritis in the hip may lick the skin over the sore joint. A hot spot in an odd place can be a clue to an underlying pain problem.

Boredom and stress

Some dogs lick out of boredom, anxiety or habit. A dog left alone all day may chew its paws or legs until the skin breaks. This is less common than allergies, but it's worth considering if everything else has been ruled out.

Breeds and seasons

Any dog can get one, but some get them again and again. Golden Retrievers, Labradors, German Shepherds, Rottweilers, Saint Bernards and Newfoundlands top most lists. Long, dense double coats hold moisture against the skin. Hot spots peak in warm, humid months, when fleas are active and dogs swim and pant. A dog that gets a hot spot every July is telling you something about allergies or coat care.

Hot spot healing stages

Knowing the usual timeline helps you tell whether treatment is working. These are typical for a mild hot spot that's treated promptly.

If the patch is still wet after three days of treatment, it's growing, or your dog is still licking, call your vet. A hot spot that won't dry up usually means the underlying cause isn't controlled.

Hot spot treatment

Vets follow the same basic steps, whatever the cause. Some can be done at home with guidance, and others need a clinic.

Step 1: Stop the licking

Nothing heals while your dog keeps licking. An e-collar (cone) is the most reliable choice. A soft cone or inflatable collar can work. For hot spots on a leg or paw, a clean sock or bandage may act as a barrier, but only if your vet agrees, because tight wraps cause problems.

Step 2: Clip the hair

Hair traps moisture and bacteria. A vet or groomer will clip the area, plus a margin of healthy skin around it, using clippers. Scissors are a bad idea, because a nervous or sore dog can jump and the skin is fragile. Clipping is often the single biggest step in getting a hot spot to dry.

Step 3: Clean and treat the skin

The vet will usually clean with a mild antiseptic such as chlorhexidine. Then they'll apply a medicated topical, which might be an antibiotic, a steroid or a combination. For a hot spot on a small, clean area, topical treatment alone is often enough. Larger or deeper lesions might need oral medication.

Avoid touching the area with bare fingers. It hurts, and it can carry bacteria into the wound.

Step 4: Antibiotics and pain relief

Oral antibiotics are used for serious or deep infections, for hot spots that cover a large area or when topical treatment isn't working. A short course of anti-inflammatory medication reduces pain and itch. Don't give human painkillers such as ibuprofen or acetaminophen. They're toxic to dogs.

Step 5: Fix the underlying cause

This step is the one that stops repeats. The vet may start flea control, change the diet, test for allergies, treat ears or anal glands or manage joint pain. If the cause is boredom, more exercise and play help. Ask your vet what they think started yours. If your dog has a hot spot near the ear, also read our guide on how to clean dog ears.

What to expect at the clinic

Many dogs are sore enough that the vet gives a short sedative or pain relief before clipping. That's normal, and it makes the visit kinder for everyone. The vet may also check for fleas with a comb, look in the ears and feel the hips and spine. If the same spot keeps coming back, they might suggest skin scrapings, a skin culture, allergy testing or a food trial. The visit usually takes less than an hour, and most dogs go home the same day with a cone and medicine.

Expect to give medicine for about 7 to 14 days. Keep the cone on until the skin is dry and the hair has started to come back, even when your dog seems fine. Most licking relapses happen on the day an owner takes the cone off early.

Home remedies for hot spots

Many owners ask about home remedies. A few are safe, and some are risky.

Safe to try while you arrange a vet visit:

• Gently clip the hair around the patch if your dog allows it
• Rinse with lukewarm water or sterile saline
• Pat dry with a clean towel, then keep the area open to the air
• Use a cone to stop licking

Avoid:

• Hydrogen peroxide, alcohol or tea tree oil, which sting and damage healing skin
• Human creams, especially steroid or antibiotic creams that your dog will lick off
• Wraps held on with tape or tight bandages
• Waiting more than a day if the patch is large or growing

A hot spot that is small, caught early and not painful may respond to simple home care. A big or painful one needs a vet.

Can hot spots kill a dog?

It's very unlikely. Hot spots are surface infections. But they can be serious in a small number of cases. If the infection goes deeper, a dog can get a fever, feel miserable and need stronger treatment. Dogs with weak immune systems, diabetes or Cushing's disease are at higher risk.

In practice, the bigger risk is delay. A hot spot that's ignored can cover a large area of skin in days and become a deep skin infection that takes weeks to clear. If you're unsure, don't wait.

Preventing hot spots

Prevention is mostly about controlling the itch and keeping skin dry and clean.

• Keep year-round flea control up to date
• Brush long coats often, and remove mats
• Dry your dog fully after swimming and baths, especially under the ears and in skin folds
• Manage known allergies with your vet
• Get ears, anal glands and joints checked if your dog licks the same spot repeatedly
• Give plenty of exercise and mental stimulation

Do a quick skin check once a week. Run your hands over the coat, part the fur along the hips, neck and tail base and look for redness, heat or damp patches. Catching a hot spot at the size of a coin makes treatment far easier. After a swim, a rub-down with a dry towel takes two minutes and prevents many problems.

For other causes of itchy, crusty skin, see mange in dogs, which can look similar at first.

Hot spots in older and anxious dogs

Senior dogs often develop hot spots over sore joints, because they lick the skin above an aching hip or knee. If a hot spot keeps showing up over the same joint, ask your vet about pain relief. Anxious dogs may lick the same area when they're left alone or stressed. A new routine, puzzle feeders, longer walks and, where needed, behavior help can break that habit. Treating the skin alone won't fix it.

When to see a vet

Most hot spots need professional care, because clipping and a medicated topical work best when done properly. Book a visit within a day if you see a hot spot.

Go the same day if:

• The patch is growing fast or is bigger than your palm
• There are several patches, or deep, pus-filled sores
• Your dog has a fever, is lethargic or is off its food
• The area is on the face, near the eye or too painful to touch
• A smell, thick pus or bleeding suggests a deeper infection

Keep your dog from licking it on the way. For more on skin and coat issues, visit our skin and coat section.