What is a Hot Spot

What is a hot spot?

Canine hot spots, also called pyotraumatic dermatitis or acute moist dermatitis, are red, inflamed skin lesions that develop rapidly, ooze, and may contain pus. These can occur anywhere on a dog's body, though they are most commonly found on the head, legs, and hips. These painful, itchy, and odorous sores can be quite noticeable or hidden beneath tangled fur.

What causes hot spots?

Hot spots typically result from self-inflicted trauma when a dog scratches an itch so intensely that it creates an open wound. Various factors can trigger the initial itch in dogs, including:

• Allergies, such as food or inhalant allergies that lead to itching

.• Reactions to insect bites from fleas, mites (Sarcoptes, Cheyletiella), or other small insects (e.g., caterpillars, bees, wasps, lice, gnats, or mosquitoes).

• Ear infections. Bacteria or yeast in the ear canal can be so irritating that the dog scratches at its ear, leading to hot spots on the ear flap, behind the ear, or on the neck.

• Pyoderma. Primary skin infections caused by bacteria or yeast may prompt the dog to scratch an area excessively, resulting in a secondary hot spot.

• Poor grooming. Dogs with neglected coats may bite at tangles, causing open wounds. Matted fur prevents air from reaching the skin and retains moisture after a dog swims or is caught in the rain, creating an ideal environment for a hot spot.

• Boredom. Like humans, dogs can develop bad habits. Instead of biting their fingernails, bored dogs lick areas that are easily accessible. When they lie down, their feet and forearms are right under their faces, often leading to hot spots there.

• Orthopedic problems. Dogs with arthritis or back issues tend to lie down frequently. Resting on one side can cause abrasions over pressure points, like hips or hocks (ankles), where bony protrusions have minimal muscular padding, particularly in older dogs with reduced muscle mass. When the dog licks the abrasion, a hot spot develops. Dogs may also lick or chew at deteriorating joints as humans might rub a sore knee to alleviate pain, leading to hot spots.

• Anal gland inflammation. Infected or impacted anal glands are painful and troublesome. Dogs lick the area around the rectum, causing hot spots under or on top of the tail.

"Hot spots can dramatically increase in size in a very short period of time."

When a dog licks the sore spot, it irritates the superficial nerve endings in the skin, which triggers more itching followed by further licking, biting, and scratching. This lick-itch-lick cycle is the root of the self-trauma that leads to hot spots. Hot spots can grow significantly larger in a very brief time. Pet owners might leave for work after noticing a tiny red spot and return at the end of the day to find a raw lesion the size of a pancake.

More on Hot Spots on our next blog.