A hot spot is a raw, inflamed patch of skin that appears suddenly on a dog and can grow rapidly, sometimes expanding from a small irritated area to a painful, oozing lesion within hours. The medical name is acute moist dermatitis, and it’s one of the most common skin conditions veterinarians treat, especially during warm, humid months.
What a Hot Spot Looks Like
Hot spots typically appear as red, wet, irritated patches of skin that may be oozing pus or clear fluid. The fur around the area often looks matted or stuck down, and you might notice hair loss over and around the lesion. The skin underneath is usually bright red or raw-looking, and it can feel warm to the touch, which is where the name comes from.
They most commonly show up on the head, neck, hips, and limbs, though they can appear anywhere on the body. The affected area is intensely itchy and painful, so your dog will likely lick, chew, or scratch at it obsessively. That constant irritation is part of what makes hot spots grow so fast: the licking and scratching damages more skin, which creates more inflammation, which drives more licking and scratching. A spot the size of a coin in the morning can be palm-sized by evening.
What Causes Hot Spots
A hot spot starts with anything that makes a dog scratch, lick, or bite at one area of skin. The initial trigger can be surprisingly minor: a flea bite, a small scrape, an allergic reaction to pollen or food, an ear infection that causes head-scratching, or even boredom-driven licking. Once the dog breaks the skin’s surface through repeated irritation, bacteria that naturally live on the skin move into the damaged tissue and cause infection. That infection creates more itching and discomfort, and the cycle accelerates.
Moisture is a major factor. A dog who goes swimming, plays in the rain, or gets a bath and doesn’t dry fully is at higher risk, because a damp coat traps warmth and moisture against the skin. This creates ideal conditions for bacteria to multiply. Common underlying triggers include:
- Flea or insect bites: even a single flea bite can set things off in dogs with flea allergy dermatitis
- Environmental allergies: pollen, mold, and grass allergies cause generalized itching that leads to focused scratching
- Ear infections: dogs scratch behind or below the ear, creating hot spots on the head and neck
- Anal gland problems: scooting and biting at the hindquarters can trigger hot spots near the tail base
- Trapped moisture: wet fur that doesn’t dry completely, particularly in thick or double-coated breeds
- Stress or boredom: repetitive licking that damages the skin over time
Dogs Most at Risk
Hot spots are most common in dogs with long or thick coats. Breeds like Golden Retrievers, German Shepherds, Newfoundlands, Saint Bernards, and Labrador Retrievers are especially prone. Dogs with drop ears (ears that hang down rather than stand upright) are also at higher risk, because the ear flap traps moisture and warmth, which promotes both ear infections and the scratching that follows.
Double-coated breeds face particular challenges because their dense undercoat holds moisture close to the skin and can take a long time to dry. Seasonal patterns are common: hot spots peak during summer and early fall when humidity is high, allergens are abundant, and dogs spend more time in water. Some dogs develop hot spots in the same location year after year, especially if the underlying trigger (like a seasonal allergy) isn’t addressed.
How Hot Spots Are Treated
The first step in treating a hot spot is getting the area clean, dry, and exposed to air. This usually means clipping the fur away from the lesion and a margin of healthy skin around it. For many dog owners, seeing the area fully clipped is the first time they realize how large the hot spot actually is, because matted fur often hides the true extent of the damage.
Once the hair is removed, the area is gently cleaned to remove dried discharge and debris. Your vet will typically prescribe a combination of topical treatments to fight infection and reduce inflammation, along with something to break the itch-scratch cycle. An e-collar (the plastic cone) is often essential, because even a few minutes of licking can undo progress. Many dogs need oral medication as well if the infection has spread beyond the surface or if the hot spot is severe.
With proper treatment, most hot spots improve noticeably within two to three days and heal fully within one to two weeks. The area will scab over and eventually grow new fur, though this can take several weeks longer. If your dog’s hot spot doesn’t start improving quickly with treatment, that’s a sign the underlying cause (like allergies or a deeper skin infection) needs further investigation.
What You Can Do at Home
If you catch a hot spot very early, when it’s still small, you can try gently trimming the fur around it with blunt-tipped scissors and cleaning the area with a mild antiseptic rinse designed for pets. Keep the area dry and prevent your dog from licking it. A clean, breathable e-collar is your best tool here.
However, hot spots progress quickly and are painful, which makes home care difficult. Most dogs won’t tolerate having the area clipped or cleaned without some form of pain management, and attempting it on a painful, anxious dog risks a bite. If the area is larger than a couple of inches, if it’s oozing significantly, or if your dog is in obvious distress, veterinary treatment is the faster and safer path. Delaying by a day or two while trying home remedies often allows the hot spot to double or triple in size.
Avoid applying hydrogen peroxide, rubbing alcohol, or human antibiotic ointments to a hot spot. These products can sting badly, damage healing tissue, or be toxic if your dog licks them off.
Preventing Hot Spots
Prevention comes down to two things: keeping your dog’s skin dry and addressing whatever makes them scratch. After swimming, bathing, or getting caught in the rain, dry your dog thoroughly. A towel works fine for short-coated breeds, but dogs with long or double coats often need brushing and a blow dryer on a cool setting to get the undercoat fully dry. Pay extra attention to areas where fur is densest, like behind the ears, around the neck, and near the tail.
Year-round flea prevention eliminates one of the most common hot spot triggers. If your dog has environmental or food allergies, working with your vet to manage them reduces the baseline itching that starts the cycle. Regular grooming helps too: keeping the coat clean, free of mats, and trimmed (especially in summer) allows better airflow to the skin. For dogs prone to ear infections, routine ear cleaning can prevent the head-scratching that leads to hot spots on the face and neck.
Dogs who get hot spots in the same spot every summer are almost always reacting to the same seasonal trigger. Identifying and managing that trigger, whether it’s fleas, grass pollen, or retained moisture after swimming, is the most effective way to break the pattern.