What is feline miliary dermatitis?
Feline miliary dermatitis is a term used to describe a skin condition in cats that most commonly results from an allergic reaction. The term 'miliary' is derived from the word milium, which is Latin for 'millet', as the small, crusted lesions of miliary dermatitis resemble millet seeds. Frequently, these lesions can be felt rather than seen.
What are the clinical signs of miliary dermatitis?
An affected cat will have a very itchy rash and may lick, bite, and scratch at the affected skin. In some cases, simply 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 allergic reaction itself. The most commonly affected areas include the lower spine, around the base of the tail, face, ears, neck, flanks, and belly. The hair 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 a severe skin reaction (see handouts "Flea Allergy Dermatitis in Cats" and "Flea Control in Cats” for more information).
"By far, the most common cause of feline miliary dermatitis is an allergy to fleabites."
Miliary dermatitis can also indicate an allergy to something in the cat's diet (food allergy dermatitis) or a response to an environmental allergen (see handouts “Atopic Dermatitis in Cats” and “Food Allergies in Cats” for more information). Contact dermatitis is another possibility but is rare in cats.
Miliary dermatitis may also be associated with mites, lice, nutritional deficiencies, and infectious and immune-mediated diseases.
How is miliary dermatitis diagnosed?
Diagnosis is based primarily on your cat’s medical history and clinical signs. If fleas or flea dirt are observed, or if your cat is not receiving flea prevention, the diagnosis may be presumed as a flea allergy. If another cause is suspected or if the condition does not respond to symptomatic flea treatment, skin scrapings, biopsies, allergy tests, a hypoallergenic food trial, or a referral to a veterinary dermatologist may be recommended.
How is miliary dermatitis treated?
Treatment involves removing the offending irritant or allergen and reducing your 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.
"Treatment involves removing the offending irritant or allergen and reducing your cat's clinical signs."
Topical treatments may be used in cases of parasite infection, such as mites or lice. 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 your cat feel more comfortable and reduce the constant itching while the specific treatment takes effect. Other treatments may include antihistamines, essential fatty acids, topical treatment (calming or antiseptic sprays or mousses), and cyclosporine (Atopica®).
What is the prognosis?
For most cats, the prognosis is excellent for controlling the condition. The offending allergen must be removed for long-term resolution. Depending on the climate and your cat's lifestyle, year-round monthly flea prevention may be recommended. Many cats that have an allergic cause to their miliary dermatitis respond well to intermittent corticosteroid therapy, hypoallergenic diets, antihistamines, and/or cyclosporine. Your veterinarian will determine the best treatment protocol for your cat's individual needs.
