Hot spots are caused by a dog’s own scratching, licking, or chewing in response to an itch, pain, or irritation. The damaged skin then becomes infected with bacteria that already live on your dog’s coat, which creates more itching and more scratching. This self-reinforcing cycle can turn a small irritated patch into a large, angry wound in as little as ten minutes. The real question isn’t just what a hot spot is, but what triggered your dog to start chewing in the first place.
The Itch-Scratch Cycle
A hot spot, formally called pyotraumatic dermatitis, is a surface-level skin infection that a dog essentially creates itself. Something makes the skin itch or hurt. The dog licks, bites, or scratches at the spot obsessively. That trauma breaks the skin’s surface, and bacteria that normally live harmlessly on your dog’s skin (most commonly a species called Staphylococcus pseudintermedius) rush in and multiply. The bacterial overgrowth triggers inflammation, which produces more itching, which leads to more chewing. Left unchecked, a hot spot can spread rapidly and become intensely painful.
Hot spots look different from other skin problems. They’re distinctly moist and inflamed, often oozing or sticky, with matted fur around the edges. Ringworm, by comparison, tends to look dry with patchy hair loss. If you part your dog’s fur and find a red, wet, raw-looking patch, you’re almost certainly looking at a hot spot.
Allergies Are the Most Common Trigger
The top causes of hot spots are environmental allergies and flea bite allergies. Both are more common in spring and summer, which is why hot spots spike during warmer months. Environmental allergies work the same way in dogs as they do in people: pollen, mold, dust mites, or grass trigger an immune overreaction that makes the skin intensely itchy. Dogs don’t sneeze the way we do. They scratch.
Flea bite allergy is especially potent. A dog with flea bite hypersensitivity doesn’t need a full infestation to react. A single flea bite can trigger intense itching that lasts for days, driving the dog to chew at the bite site until a hot spot forms. This is one reason hot spots can seem to appear “out of nowhere” even in dogs on flea prevention, since no preventative is 100% effective at stopping every single bite.
Food allergies can also be a factor, though they’re less common than environmental triggers. If your dog develops hot spots year-round rather than seasonally, a food sensitivity is worth investigating with your vet.
Ear Infections and Anal Gland Problems
Not every hot spot starts with an itch. Pain and discomfort from other conditions can drive the same scratching behavior. Two of the most common culprits are ear infections and impacted anal glands.
Here’s a typical scenario: an allergic dog develops an ear infection. The infection causes pain or itching deep inside the ear canal, so the dog scratches at the side of its head repeatedly. That scratching breaks the skin on the cheek or below the ear, bacteria move in, and a hot spot forms. The hot spot isn’t the primary problem. It’s a secondary consequence of the ear infection. Wet ears from swimming are a frequent starting point for this chain of events.
The same logic applies to anal glands. When anal sacs become infected or impacted, they cause discomfort that makes a dog lick and chew at its rear end. If your dog’s hot spot is near the base of the tail or hindquarters, the anal glands are a likely underlying cause.
Moisture and Thick Coats
Dogs with dense or double coats are more prone to hot spots because their fur traps moisture against the skin. After swimming, bathing, or getting caught in rain, a thick coat can stay damp for hours. That warm, moist environment is ideal for bacterial growth on the skin’s surface, and any minor irritation can quickly escalate.
Breeds like Golden Retrievers, Labrador Retrievers, German Shepherds, and Saint Bernards are particularly susceptible. If your dog has a thick coat and loves water, drying them thoroughly afterward (especially around the ears, neck, and hindquarters) is one of the simplest things you can do to reduce hot spot risk.
Boredom and Anxiety
Sometimes there’s no underlying itch at all. Dogs that are bored, understimulated, or anxious can develop a habit of licking themselves the same way a person might bite their nails. When a dog lies down, its paws and forearms are right in front of its face, making those areas easy targets for repetitive licking. Over time, this habitual licking damages the skin enough to start the infection cycle.
Behavioral hot spots tend to show up in predictable spots (the front legs and paws) and may recur even after the skin heals if the underlying boredom or anxiety isn’t addressed. More exercise, mental enrichment, and in some cases anti-anxiety medication can break the pattern.
How Hot Spots Are Treated
Treatment has two parts: clearing the hot spot itself and identifying what caused it.
For the hot spot, the first step is clipping the fur around the lesion so the skin can dry out and be cleaned. This matters more than it might seem, because trapped moisture under matted fur is what keeps the infection thriving. Once the area is exposed, it’s disinfected and treated with topical products to calm the inflammation. If the hot spot is large, if there are multiple spots, or if your dog is extremely itchy, oral medications to reduce inflammation and fight infection may be needed as well.
One important caution: don’t reach for human skin ointments. Many contain ingredients like zinc oxide that are toxic to dogs when licked, and your dog will almost certainly lick the area.
The second, more important part of treatment is figuring out what set off the scratching in the first place. A hot spot that gets treated but whose underlying cause is ignored will come back. If your vet suspects allergies, you may discuss flea prevention, dietary changes, or allergy management. If the hot spot is near the ear, expect your vet to look inside the ear canal. If it’s near the tail, they’ll likely check the anal glands. The location of a hot spot is often the biggest clue to its cause.
Reducing the Risk of Recurrence
Since hot spots are a symptom of something else, prevention means staying ahead of the triggers:
- Flea control: Year-round flea prevention is the single most effective measure for dogs with flea bite sensitivity.
- Coat care: Dry your dog thoroughly after swimming or bathing, paying extra attention to the ears and any areas with dense fur.
- Allergy management: If your dog has known environmental allergies, work with your vet on a long-term plan rather than treating each hot spot as a one-off event.
- Ear and anal gland maintenance: Regular ear checks (especially for floppy-eared breeds) and anal gland expression when needed can prevent the discomfort that leads to scratching.
- Mental stimulation: For dogs prone to habitual licking, puzzle toys, regular exercise, and training sessions can redirect the behavior before skin damage starts.
Dogs that get one hot spot are likely to get another, especially during warm, humid months. Recognizing the early signs of excessive scratching or licking and intervening before the skin breaks is the most practical way to stop a hot spot before it starts.