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 cat 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 or the hip areas. Hot spots are uncommon in cats compared to dogs.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 cat will scratch without letup
Diagnostic tests are needed to recognize acute moist dermatitis and exclude other diseases, as well as to determine the underlying cause of the hot spot. However, your veterinarian can usually make a preliminary diagnosis based on a history of rapid onset and the clinical appearance of the lesions.
Treatment for acute moist dermatitis may include one or more of the following:
Clipping and cleaning of the affected areas. Lesions often are more extensive than they initially appear. Clipping the hair in the area is important to allow proper cleaning of the affected skin. Antibacterial solutions (chlorhexidine) or drying solutions (Burrow's solution) combat infection and decrease pruritus (itchiness).
Interruption of the pruritic cycle. This is crucial to successful treatment. Once the cycle has been triggered, it is important to stop it so as to prevent self-mutilation. Orally-administered cortisone-like drugs often are used for a short period of time to make the cat more comfortable. Your cat may be more hungry and thirsty while receiving corticosteroids – this is a common side effect of this medication. As a consequence, the cat may need to urinate more frequently than normal. Some cats may also pant as a consequence of corticosteroid therapy.
Secondary bacterial infection must be treated when present. In some cases, damage is so extensive that bacteria proliferate, resulting in secondary infection. In such instances, an antibiotic may be prescribed for 2 to 3 weeks.
Identification and treatment of the underlying cause is important to prevent recurrent episodes of acute moist dermatitis. Most cases are secondary to flea allergy and aggressive flea control usually is necessary.
Home Care and Prevention
Clean the affected areas with antibacterial and astringent products daily until healing is complete. Make sure that your cat has sufficient water while receiving corticosteroids. House soiling incidents may occur during corticosteroid therapy if the cat is not allowed outdoors frequently enough.
If your cat has 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 also should apply an appropriate insecticide or repellent to your cat to prevent flea bites.