Feline miliary dermatitis is a skin disease caused by an allergic reaction to a number of agents, including the bites of fleas, mites and lice. Bacterial and fungal skin infections, nutritional disturbances and drug reactions can also produce miliary dermatitis.
Flea Bite Dermatitis
In this condition, the skin is severly itchy and may break down, producing new patches of skin that becomes infected from intense scratching. Localized or generalized eosinophilic plaques may develop as a consequence. Eosinophilic plaque is an itchy skin condition that occurs in young to middle-aged cats, with average age being three years. It is characterized by round, raised, red plaques located on the abdomen and inside thighs and accompanied by hair loss. Although cats are especially resistant to flea bites and can harbor many fleas without symptoms, in susceptible animals a single bite once or twice a week is sufficient to produce the allergy. Symptoms are most commonly seen in the middle of summer (flea season). However, once the cat is exposed, if fleas live in the house, itching may persist year-round. Itching tends to persist long after fleas have been destroyed.
Flea bite dermatitis is suspected by seeing the characteristic skin rash and by finding fleas on the cat. You can check for fleas by standing your cat over a sheet of white paper and brushing the coat. White and black grains of sandy material that drop on the paper are flea eggs and feces. The diagnosis is confirmed by a skin test. When fleas are present, treat infestation first. In the absence of fleas, an effort must be made to determine the cause of the miliary dermattitis. Cortisone tablets or injections that block the allergic reaction and relieve the itching are useful in long-term management in some cats. These should be used under veterinary supervision because of potential side effects. Sores may be treated with a topical antibiotic/steroid ointment. Desensitization is not very effective.