A dog with a hot spot on its neck.

Acute Moist Dermatitis (Hot Spots) in Dogs

Overview of Canine Hot Spots

Acute moist dermatitis, also commonly known as “hot spots” or “pyotraumatic dermatitis,” are acute, moist, localized, inflamed, and rapidly progressive bacterial infections of the skin. Acute moist dermatitis is a very common skin disease for dogs.

The precise sequence of events leading to hot spots is not known, but anything that can initiate an itch-scratch cycle can lead to this condition. The sequence most likely begins with something that irritates the skin and the body’s response is either to itch or become inflamed. The inflammation then causes the dog to lick or chew the area, which further damages the skin, and creates a cycle of self-trauma from itching, scratching, and chewing.

Common Causes

The most common skin irritant that causes hot spots is fleas.

Other reasons for hot spots include:

Less common causes of hot spots include ringworm (dermatophytosis), drug reactions, autoimmune disease (where the body fails to identify self-components and reacts against normal tissues), and vasculitis (inflammation of blood vessels).

Hot spots are most common in dense, long-haired, and heavy-coated breeds, and are more prevalent during the summer months. Typical locations for “hot spots” are the sides of the face, around the neck, dorsal back, and the flank (lateral thigh). They can occur in any breed, but are more common in Golden Retrievers, Labrador Retrievers, St. Bernards, and German Shepherds. Young dogs (less than 4 years old) seem to be predisposed. It is rarely diagnosed in cats.

The role of bacteria in the development of hot spots is also unclear. Some cases of acute hot spots seem to be initiated by folliculitis (inflammation and infection of hair follicles), and this seems to be common in St. Bernards and Golden Retrievers. Other affected dogs do not seem to have an important bacterial component and respond to clipping of the hair, cleansing of the skin, and corticosteroid therapy.

Key Points about Hot Spots

What to Watch For

Clinically, the lesions of acute hot spots are secondary to self-inflicted trauma. Strangely, even severe self-trauma in some dogs will not create a hotspot, while in others, minimal self-trauma may do so.

Typically, dogs with hot spots will exhibit the following:

Diagnosis of Hot Spots in Dogs

Diagnosis of hot spots is generally based on history, clinical signs, and physical examination. Diagnostic tests may be needed to confirm the diagnosis 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.

Tests to evaluate for other or related diseases may include:

Hot Spot Treatment Options

Treatment for hot spots may include one or more of the following:

Home Care of Hot Spots

Tips for treating a dog’s hot spots include:

Preventing Dog Hot Spots

If your dog has a flea allergy and is prone to develop hot spots, you should be aggressive with your flea control program. In addition to treating the environment, you should also apply an appropriate insecticide or repellent to your dog to prevent flea bites. Depending on your area of the country, flea prevention medications are recommended year-round.

Regular bathing, grooming, and clipping of the hair coat can be beneficial in long-haired dogs during the summer months to prevent reoccurrence. It is important to pay particular attention and keep ears clean and dry after swimming or grooming.

Prognosis for Dogs with Hot Spots

The prognosis for dogs with hot spots is very good with appropriate treatment.