Acute Moist Dermatitis (Hot Spots) in Dogs

Acute moist dermatitis, also known as hot spots, are localized, moist, reddened bacterial infections of the skin. A hot spot starts because something irritates the skin. The body's response is either to itch or become inflamed. The itching then causes the dog to lick or chew the area, which further damages the skin, and creates a cycle of itching, scratching and chewing. 

Hot spots can be caused by anything that irritates the skin and initiates an itch-scratch cycle, but the most common irritants are fleas. Other causes are allergies (flea, inhalant, food), parasitic disease (sarcoptic and demodectic mange), anal gland disease, poor grooming, tick and mosquito bites, burrs, and summer heat. They are most common in long-haired and heavy-coated breeds, and are more prevalent during the summer months.

Typical locations for "hot spots" are the side of the face and the flank areas. Golden retrievers, Saint Bernards and young dogs seem to be predisposed to acute moist dermatitis.

What to Watch For 

Typically, your pet will exhibit the following:

Areas of hair loss with very red skin that is moist and oozing

In some cases, the skin becomes crusty or scabbed

Intense scratching. Hot spots are extremely itchy and your dog will scratch without letup

Diagnosis

Diagnostic tests are needed to recognize acute moist dermatitis and exclude other diseases. However, your veterinarian can usually make a preliminary diagnosis based on a history of rapid onset and the clinical appearance of the lesions.