Feline Miliary Dermatitis
What is feline miliary dermatitis?
Feline miliary dermatitis is a general term used to describe a skin condition in cats that most commonly results from an allergic reaction. Since the most common allergic dermatitis or skin allergy in the cat is flea allergy dermatitis, the two terms have become synonymous.
"In some cases, even touching the affected skin causes the cat to scratch, lick, or twitch."
The term miliary means resembling millet seeds. Clinically, the patient has a very itchy rash and may lick, bite and scratch at the affected skin. In some cases, even touching the affected skin causes the cat to scratch, lick, or twitch. The rash quickly progresses to small lesions with scabs on them; these may be the result of self-trauma, or the result of the allergic reaction itself. The most commonly affected area is along the lower spine and around the base of the tail, but the neck, flanks and belly may also be involved. The coat often becomes thin in affected areas. In severe cases, the rash becomes infected, which is seen as pustules or "pimple-like" lesions. Affected cats spend a lot of time grooming and scratching the affected areas.
What causes miliary dermatitis?
By far the most common cause of feline miliary dermatitis is an allergy to fleabites. Some cats become extremely sensitive to fleabites and a single bite may be enough to provoke quite a severe skin reaction.
Miliary dermatitis can also represent a reaction to other irritants or allergens. Parasites such as Cheyletiella (fur mites or "walking dandruff"), harvest mites, lice and ear mites can be responsible for causing the clinical signs of miliary dermatitis. It can indicate an allergy to something in the cat's diet (food allergy dermatitis) or a response to an inhaled allergen (atopy). Contact dermatitis or contact allergies are another possibility, but this is rare in cats. The most likely contact allergens are synthetic materials such as carpets within the house, and plant materials such as sap or pollen.
How is miliary dermatitis diagnosed?
"The diagnosis is often presumed to be flea allergy."
Diagnosis is based primarily on medical history and clinical signs. If fleas or flea dirt are observed or if the cat is not on a flea preventive, the diagnosis is often presumed to be flea allergy. If another cause is suspected or if the condition does not respond to symptomatic flea treatment, skin scrapings, biopsies, serum IgE allergy tests, a hypoallergenic food trial or a referral to a veterinary dermatologist may be recommended.
How is miliary dermatitis treated?
"Corticosteroids to make the cat feel more comfortable and reduce the constant itching."
Treatment involves removing the offending irritant or allergen and reducing the cat's clinical signs. A flea preventive is applied if flea allergy dermatitis is suspected. Live fleas are seldom seen on cats, due to their fastidious grooming habits. Therefore, first-time cases of miliary dermatitis are often treated as flea allergy dermatitis unless proven otherwise. Medicated baths, dips or sprays may be used in cases of parasite infection such as cheyletiellosis. A hypoallergenic food trial is recommended in cases suspected of having a food allergy as a component of the allergy. Your veterinarian may prescribe a short course of anti-inflammatory drugs such as corticosteroids to make the cat feel more comfortable and reduce the constant itching while the specific treatment takes effect.
What is the prognosis for a cat diagnosed with miliary dermatitis?
For most cats, the prognosis is excellent for control. The offending allergen must be removed for long-term resolution. Depending on the climate and the cat's life style, year-round monthly flea preventive may be recommended. Many cats that have an allergic cause to their miliary dermatitis respond well to intermittent corticosteroid therapy and hypoallergenic diets. Your veterinarian will outline the best treatment protocol for your cat's individual needs.