You've probably heard one of these at the dog park:
- "It came out of nowhere."
- "It wasn't there this morning."
- "I thought it was a bug bite."
All three are typical of a hot spot. And a lot of them show up after the same thing: a thick coat that got wet and never fully dried.
Short answer: a hot spot is a patch of red, wet, painful skin that a dog makes worse by licking and scratching. Vets call it acute moist dermatitis. It can appear within hours. Itch from fleas or allergies is the usual starting point, and a coat that stays wet against the skin is one of the things that sets it off, which is why vets see more of them in thick-coated dogs after swimming, baths and rainy walks.
What does a hot spot look like on a dog?
A hot spot is easy to miss on a fluffy dog because the hair around it mats over the top. Part the fur and you'll usually see:
- A red, wet, raw patch. It looks moist or oozing, and the hair over it is gone or falling out (AKC).
- A clear edge. The sore has a defined border, like it was drawn on, rather than a general redness.
- Matted, crusty fur around it. Fluid dries into the surrounding hair, and the sore can smell (VCA).
- A dog that won't leave it alone. Constant licking, chewing or scratching at one place, and flinching when you touch it.
Many start small enough to pass for an insect bite. What gives them away is speed: VCA notes they can appear in a couple of hours and grow quickly from there.
Where to look
- Head and neck, including under the ears. Cornell links ear-area hot spots to ear infections.
- Hips and the outside of the thighs.
- Legs.
- Base of the tail. Easy to miss unless you lift the tail and look (Cornell).
Why a wet coat sets them off
A hot spot almost always starts with an itch. Fleas, allergies, an ear infection or an insect bite make the dog lick and scratch. The licking breaks the skin, bacteria move in, the skin gets itchier, and the dog licks more. That loop is what turns a small spot into a big one in a day.
Moisture is what helps the loop get going. Here is how vet sources put it:
- AKC: dogs that are often wet from swimming, baths or bad weather are more prone, because their coats hold moisture against the skin.
- Cornell: swimming, wading or playing in warm rain can trigger hot spots, especially in dogs whose thick coats don't dry fully. Matted areas hold moisture next to the skin.
- VCA: matted fur keeps air from reaching the skin and holds water after a dog swims or gets caught in the rain.
- Merck Veterinary Manual: anything that turns normally dry skin into moist skin can let bacteria overgrow.
The top of a thick coat dries in minutes. The layer against the skin can stay damp for hours, and you can't see it. Run your fingers to the skin on the hips or behind the ears an hour after a rainy walk, and on a double-coated dog it's often still wet.
The honest version: rain alone doesn't give a dog a hot spot. Itch plus skin that stays wet is the combination to avoid.
Which dogs get them most
Vets name the same breeds again and again, and almost all of them are big dogs with thick or double coats:
- Golden retrievers and Labrador retrievers
- German shepherds
- Saint Bernards and Newfoundlands
- Rottweilers
That list comes from AKC, Cornell and PetMD. They're also the dogs that love water and the dogs whose undercoat takes longest to dry. Warm, humid weather adds to it, so the risk doesn't end when summer does: a mild, rainy fall day is exactly the kind of weather that keeps a thick coat damp.
Found one? What to do today
A hot spot is a vet visit, not a wait-and-see. While you're getting an appointment, the sources agree on a few things you can do:
- Stop the licking. A cone, or a T-shirt or body suit over the spot (PDSA).
- Keep it clean and dry. Gently clean the area and let air reach it.
- Don't reach for scissors. VCA warns it's easy to cut the skin when you trim around a hot spot. Clipping is what the vet does.
- Don't put human creams on it without asking your vet first.
At the clinic, a vet will usually clip the hair, clean the skin, treat the infection and the itch, and look for what started it, such as fleas, allergies or an ear problem. AKC says many hot spots improve within about three to seven days once treatment starts.
The spot is spreading, bleeding or has pus, your dog is in obvious pain, or it keeps coming back. Cornell treats a sore that's more than a day old as likely infected.
After a wet walk: dry to the skin
Because the risk is a coat that stays wet, the best habit is simple: don't let your dog lie around damp. Cornell's advice for thick and double coats is to dry them thoroughly, with a blow dryer if needed.
A drying routine for thick coats
- Towel first, pressing, not rubbing. Rubbing tangles long hair, and tangles hold water.
- Dry the hidden places. Behind the ears, the neck, armpits, the hips and under the tail.
- Use a dryer on cool or low. Push the air against the grain so it reaches the skin, not just the top coat.
- Check with your fingers. If the skin feels damp, you're not done.
- Brush out mats. Regular brushing removes loose undercoat and the mats that hold water (VCA, Cornell).
Plenty of big dogs won't stand for a blow dryer, which is where things get hard. One customer put it this way:
“She's a Great Pyrenees who doesn't like blow dryers, so drying is a chore, especially if there's a downpour.”
Sheba T. · Puddle Jumper review
Her fix was to keep most of the coat from getting soaked in the first place. In the same review: “The coat keeps the bulk of her body dry.”
Keep the coat drier to begin with
A full-body raincoat covers the back, belly and all four legs, so on a rainy walk the water lands on a waterproof shell instead of soaking into the undercoat. On snowy days, a waterproof snowsuit does the same job against melting snow. Less water in the coat means less to dry and less time with damp skin.
To be clear about what a raincoat does and doesn't do: it keeps the coat drier. It doesn't treat a hot spot or stop one caused by fleas or allergies. The head, neck and paws still get wet, so still dry behind the ears and check the neck when you get home. Our rain gear is made for medium and large dogs, and the Puddle Jumper is the one with full leg coverage. For fit, see how to choose a raincoat for a big dog.
Horse owners know skin that stays wet for days as "rain rot," a bacterial infection called dermatophilosis. The Merck Veterinary Manual says dogs rarely get it, and it isn't the same thing as a hot spot. It's the same lesson, though: skin that stays wet for a long time is skin in trouble.
Quick answers
Can rain cause hot spots on dogs?
Not on its own. Rain that soaks a thick coat and doesn't dry is one of the triggers vets list, usually on top of an itch from fleas, allergies or ears. Drying your dog to the skin after wet walks takes that trigger away.
Can swimming cause hot spots?
It's one of the most common setups: a water-loving retriever with a thick coat that stays damp for hours. Rinse and dry thoroughly after a swim, especially in warm weather.
How fast do hot spots spread?
Fast. They can appear within hours and grow noticeably in a day, which is why it's worth calling the vet early.
Will a hot spot go away on its own?
Don't count on it. The lick and itch cycle usually keeps it going, and a sore older than a day is likely infected. See a vet.
Are hot spots contagious?
No. Hot spots don't spread from dog to dog. The cause, like fleas, can affect other pets in the house, so treat that too.
Is my dog's wet smell related?
The same damp undercoat is behind both. We cover the smell side in wet dog smell: why it happens and how to get rid of it.
This article is general information, not veterinary advice. If you think your dog has a hot spot, talk to your vet.
