Miliary Dermatitis in Cats – Causes, Symptoms and Treatment




Miliary dermatitis (also known as miliary eczema, papulocrusting dermatitis or scabby cat disease) isn’t a specific disease but a disease complex. It is characterised by a red and crusty rash around the head, neck and back, often with intense itching (pruritis).

The name miliary dermatitis is derived from the lesions which have a millet seed type appearance.

What causes miliary dermatitis in cats?

There are a number of causes, the most common include:

  • Flea bite hypersensitivity. It is believed that up to 80% of cats with miliary dermatitis have flea bite hypersensitivity. Even if you don’t see any fleas or your cat is strictly indoors, it is still possible he has fleas. Just one flea is enough to cause an allergic reaction.
  • Allergies, inhalant (such as dust or pollen), food, contact and insect (such as mosquitoes).
  • Ringworm a common fungal infection on the skin which causes circular lesions. Kittens are especially vulnerable, Persian cats and related breeds also have a higher incidence.

Other causes of miliary dermatitis may be due to:

  • Bacterial infections or overgrowth.
  • Yeast infections or overgrowth.
  • Mites including cheyletiellosis, ear mites, notoedric mange and demodicosis.

    cheyletiellosis
  • Immune-mediated diseases such as eosinophilic granuloma complex, systemic lupus erythematosus or pemphigus.
  • Drug reaction.
  • Certain tumours.
  • Biotin and fatty acid insufficiency.

In some cases, the cause can not be determined.

What are the symptoms of feline miliary dermatitis?

Miliary dermatitis in cats

  • Red, crusty bumps and papules, especially around the head, ears, neck, and back (dorsal), often with intense itching. In severe cases, the whole body may be affected.
  • As the head and neck areas are within reach of the claws, scratching can lead to self-trauma, resulting in large and often open scabs (known as excoriations).
  • Hair thinning or loss around the affected area.
  • Scratching, licking and biting the affected area.

How is feline miliary dermatitis diagnosed?




miliary dermatitis on cat

Your veterinarian will perform a physical examination of your cat and obtain a medical history from you including if the miliary dermatitis is seasonal, if your cat has any concurrent diseases, what food he is eating and if he is on any medications or treatments, is the cat indoors/outdoors and does he receive regular flea treatment?

The location of the lesions may provide a clue as to the cause. If they are close to the base of the tail then fleas are usually the culprit. If they are around the head and ears, fleas, mites or food allergy may be the cause.

In many cases, your veterinarian may recommend treating your cat for fleas, which is by far the most common cause of miliary dermatitis, to see if the problem resolves. If there is no improvement he may decide to run the following tests:

  • Biochemical profile, complete blood count and urinalyis are baseline tests to evaluate the overall health of your cat and look for underlying medical conditions.
  • Analysis of coat brushings, skin scrapings, and fur samples to check for parasitic infections such as mites, fleas or fungal infections.
  • A DTM (dermatophyte) culture for fungal infections. Hairs will be plucked from the affected area or a toothbrush will be used to collect samples which are then cultured on a special medium.
  • A fecal examination may be performed to detect the presence of intestinal parasites.
  • Skin biopsy.
  • Blood serum IgE tests.
  • Skin scrapings are scrapings of several layers of skin which are they evaluated under a microscope to look for the presence of mites, fungal infections and bacterial infection.
  • Skin culture involves taking a sample of skin and growing it on a culture to look for bacterial infection.
  • Skin prick test to see if inhalant antigens are the cause. An area of skin is shaved and a tiny amount of several common allergens are pricked onto the skin to see if there is a localised reaction.
  • Food trials. If a food allergy is suspected, your cat will be placed on a food trial which involves giving him a novel source of food (such as kangaroo or lamb) for several weeks, excluding all other foods, including treats. If the miliary dermatitis improves, the cat will then be put back on his normal diet to see if the miliary dermatitis returns.

How is feline miliary dermatitis treated?

Treatment of feline miliary dermatitis depends on the cause of the problem.

  • Removal of the fleas from the cat and environment. Strict flea control will need to be performed routinely to ensure the miliary dermatitis doesn’t recur. Note: I battled flea allergy dermatitis with my cat (his skin is pictured in the top image) for years. He was treated with topical flea products monthly, but it wasn’t working. I eventually switched him to Comfortis and the miliary dermatitis resolved almost immediately.
  • The same goes for mites, mange or fungal or yeast infections. Treat the cause and miliary dermatitis should go away.
  • If intestinal parasites are found to be the cause, treatment with the appropriate medication to eliminate them.
  • If your cat is found to have food allergies, he will be switched to a hypoallergenic diet, or a novel source of protein, or avoidance of the particular allergen. It may take some investigating to determine the exact ingredient which is causing the allergy.
  • Avoidance (where possible) if other non-food related allergies are the cause.
  • Antibiotics for secondary skin infections, if required.

In addition to the above treatments, fatty acids, shampoos, antihistamines, and corticosteroids to relieve itching and inflammation.

Related content:

Hair loss in cats   Cat symptoms   Poor coat condition in cats   Scabs on cats




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