Dog & cat health · Vet-reviewed guide

Dog Hot Spot: Causes and Treatment

A hot spot can go from a small damp patch to an angry, oozing sore in a matter of hours. They're a signal that something is bugging your dog's skin.

Quick answer: A dog hot spot is a red, raw, often oozing patch of skin that flares up fast when a dog licks, chews, or scratches one spot over and over, the medical name is acute moist dermatitis. The scratching itself turns a small irritation into a painful, infected sore, sometimes overnight.

The single most important thing to understand is that a hot spot is almost always a symptom of something else: a flea bite, an allergy, trapped moisture, or an ear or skin problem that started the itch. That is why treating just the spot, and not the underlying trigger, so often leads to it coming back. Care means gently cleaning and drying the area, stopping the dog reaching it (a cone), and seeing a vet if it is large, spreading, or not healing, because a real hot spot often needs the hair clipped and, sometimes, prescribed medication. This guide covers what causes them, safe care, and when the vet is needed.

About Apoquel (oclacitinib): this is a prescription medication your veterinarian can prescribe. Read our guide, or ask us if you need help sourcing it.

What a hot spot is

A hot spot, or acute moist dermatitis, is a localized area of inflamed, infected skin created by the dog's own licking and scratching.² It is warm, red, moist, often painful, and can grow quickly as the dog keeps worrying at it. They show up most in warm, humid weather and in thick- or long-coated dogs.

Why they form, it's almost always secondary

This is the part that matters for stopping them coming back. A hot spot starts because something made the dog itch or hurt in that spot first.¹ Common triggers include:

• Flea bites or other parasites
• Allergies (flea, food, or environmental)
• Trapped moisture from swimming, baths, or a damp coat
• An ear infection (hot spots near the ear), or an anal-gland problem (near the tail)

Treat only the spot and the trigger stays; the hot spot returns. Finding the underlying cause is half the treatment.

Safe home care while you get to the vet

For a small, early hot spot in an otherwise-well dog: gently clip or part the hair around it if you can do so without hurting your dog, clean it with a mild, pet-safe antiseptic, keep it dry, and stop your dog licking it with a cone.² Do not rely on human ointments a dog will just lick off, and do not cover it tightly, hot spots heal better dry and open. If it is anything more than small and early, see a vet.

When to see a vet

See a vet if the hot spot is large, spreading, very painful, oozing pus, or not improving in a day or two, or if your dog keeps getting them.¹ A vet often needs to clip and clean the area properly and may prescribe medication for the infection and the itch, plus help you find the underlying trigger. Any prescribed medicine must come from a vet. See how our vet prescription service works. For the itch behind it, see our guide on why your dog is itching.