Bottom line A hot spot is a red, weepy, itchy patch of skin that usually starts from something small — a flea bite, an allergy flare, or moisture trapped under the coat — and blows up fast because the dog keeps licking and chewing it. Mild, early ones can improve with clipping, cleaning, and stopping the licking, but anything large, oozing, or painful deserves a vet visit, since infected hot spots often need prescription meds.
Not veterinary advice A hot spot can look small on the surface and still be infected underneath. This guide is general education, not a diagnosis. If the area is spreading, painful, or not improving within a day or two, have your own veterinarian look at it before it gets worse.

What a hot spot actually is

A hot spot is a red, wet, inflamed patch of skin that seems to appear overnight — usually because your dog has been licking, scratching, or chewing one itchy spot until it turns raw. Vets call it acute moist dermatitis or pyotraumatic dermatitis.[2] The "hot" part is literal: the area is warm, oozy, and sore, and the hair in the middle falls out, leaving a bare, angry-looking circle.[3] The scary part is how fast it grows. What starts as a coin-sized irritation can double within hours, because the licking feeds the cycle — more damage, more itch, more licking.[1]

Why they start (and spread fast)

The trigger is almost always something small that made your dog itchy or damp in the first place. The usual culprits are flea bites, allergies (food or environmental), insect bites, and moisture trapped under the coat after a swim or a bath.[2] Once the skin is irritated, your dog goes after it, and the bacteria that already live on healthy skin jump into the broken skin and start an infection.[3] That's the key thing to understand: a hot spot isn't a skin disease on its own — it's a scratch-and-lick injury that got infected, with an underlying itch you still need to find.[1]

Which dogs get them most

Any dog can get one, but thick- or double-coated breeds are over-represented. Golden Retrievers, Labrador Retrievers, German Shepherds, and similar dogs with dense undercoats trap heat and moisture against the skin, which is exactly the environment hot spots like.[1] Dogs that swim a lot or live somewhere hot and humid get more of them for the same reason — a damp coat that never quite dries is a perfect setup.[3]

How to treat one at home

For a small, early hot spot, you can try a home-first approach: gently clip or trim the hair around the area so it can dry and you can actually see what you're working with, then clean it with a mild, pet-safe antiseptic like chlorhexidine.[2] The single most important step is stopping the licking — an Elizabethan collar (the "cone") or a recovery suit — because nothing heals while your dog keeps re-opening the spot.[1] Whatever cleanser you reach for, make it one meant for pets and approved by your vet rather than the human medicine cabinet, which can sting or make the skin worse.[3]

When to call the vet

Call your vet if the spot is large, spreading, painful, or not improving within a day or two — or if your dog seems feverish, lethargic, or won't stop crying at the area.[1] Infected hot spots usually need more than a wipe: your vet may clip the area, prescribe topical or oral antibiotics, and add a steroid or anti-itch medication to break the scratch cycle.[2] The vet visit also matters because the real fix is finding the trigger — a flea problem, an allergy, or an ear infection — so the spot doesn't come right back.[3]

How to prevent them

Prevention is mostly about the trigger, not the spot. Keep up with year-round flea and tick control, dry your dog's coat thoroughly after swimming or bathing, and treat any underlying allergy your vet identifies.[3] For thick-coated breeds, regular grooming to keep the undercoat from matting helps air reach the skin.[1] And if you catch your dog fixating on one spot — licking, chewing, or rubbing — step in early, before it turns into a full hot spot.[2]

FAQ

Can hot spots heal on their own?

Small, early ones sometimes improve if you clean the area and stop the licking. But an infected hot spot rarely clears up without help, and leaving it can let it spread fast — so when in doubt, get it checked.

Is a hot spot contagious to people or other pets?

The hot spot itself isn't contagious — it's your dog's own bacteria overgrowing on broken skin. The underlying trigger (like fleas or mites) can be a different story, so treat the root cause too.

Should I shave my dog to treat hot spots?

Clipping the hair around the spot helps it dry and heal, but shaving the whole coat usually isn't necessary and can irritate sensitive skin. Your vet can show you the right amount to clip.

Sources

  1. American Kennel Club — Hot Spots on Dogs: Causes, Treatment, and Prevention — akc.org
  2. VCA Animal Hospitals — Hot Spots in Dogs — vcahospitals.com
  3. Cornell University College of Veterinary Medicine — Hot Spots — vet.cornell.edu