Occasionally, my feline patients come in for multiple small scabs on an area of their body called miliary dermatitis. Oftentimes, there is accompanying hair loss and sometimes itching. This type of skin sign is not from scratching or trauma, it is actually an eruption (kind of like hives can erupt, so can miliary dermatitis!). The term miliary comes from the Latin word for millet. The small raised bumps and scabs are about the size of a millet seed and look like a rash on the skin.
Miliary dermatitis is the name for a skin reaction in cats that is characterized by multiple small seed-like scabs on the body. It is the most common skin reaction seen in cats, and is unique to cats! These small scabs develop as a result of numerous underlying triggers. The most common cause of miliary dermatitis is due to allergies.
Two great products you can purchase over the counter to help treat your cat with itchy skin allergies are: Zymox hydrocortisone spray : This spray contains the maximum strength of steroid in an over the counter product (1% hydrocortisone). Dermoscent’s Essential 6 Spot-on pipettes are a good product to restore the natural skin barrier and improve the skin’s immune function.
Miliary dermatitis can be triggered by an allergy to the environment (such as inhalant pollens, weeds, grasses etc. ) or allergies to food or a flea bite/other ectoparasite hypersensitivity. Other common causes in cats are due to external parasites (mites, lice), infections of the skin, or immune dysfunction. Read further to learn more about the causes of this condition and how it’s treated.
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Multiple tiny scabs on a cat is called miliary dermatitis and is a skin eruption
Rather than being a specific disease, miliary dermatitis is a skin reaction pattern. This reaction pattern is most commonly seen on the belly ,chest and around the neck. In addition to the multiple punctate scabs/ bumps on the skin, there can be redness and hair loss from over grooming. Some cats will also have scratches on the skin from itching, areas of moist infection on the skin, pink raised plaques on the skin (eosinophilic plaques), or ulcerated areas and itching.
Causes of miliary dermatitis in cats
The most common cause of miliary dermatitis in cats that I see in practice are due to environmental allergy or food allergy. However, in outdoor cats, flea allergy is a common cause as well. Other ectoparasites such as cheyletiella (lice), ear mites, and demodex mites can also produce this type of skin reaction. Bacterial skin infections (folliculitis), ringworm infection, drug reactions, hormonal deficiencies and hypereosinophilic syndrome can also cause miliary dermatitis.
Flea allergy reaction pattern in cats
Flea allergy in cats is often diagnosed by the pattern of hair loss and likelihood of exposure. Because ir can take just one flea bite to create an allergic response, it’s not always possible to find live fleas or evidence of flea dirt on a cat with a flea bite allergy.
This picture shows a classic hair loss distribution pattern in a cat with flea bite allergy. These cats will be mostly itchy over their rump and hind end. You can see this cat has barbered (over groomed) these areas.
Diagnosing and treating hair loss with many small bumps and scabs in cats
An initial diagnostic approach to a cat with miliary dermatitis includes superficial skin scrapings and evaluation of the skin cells collected under the microscope. Skin scrapings can identify mites in the skin such as demodex, determine if there is a bacterial skin infection present, allergy cells aggregating in the skin, or evidence of abnormal skin cells called acanthocytes.
Common initial treatment steps include initiating flea control (particularly if it is in the summertime) and a hypoallergenic diet. A flea control product that controls fleas as well as mites is a good choice. An example of this is, topical feline Bravecto.
Hypoallergenic foods for cats
For cats with recurrent or severe miliary dermatitis, changing their food to a hypoallergenic diet is often recommended. Examples of good hypoallergenic food choices for cats is a limited ingredient diet containing an atypical protein such as rabbit, duck or venison. The goal is to choose a protein the cat has not eaten before (so their immune system has not already mounted a reaction response).
Alternatively, a hydrolyzed diet is another excellent option for a hypoallergenic diet. Hydrolyzed diets break down proteins into small pieces between 6 and 12 kilodaltons in size. Hydrolyzed proteins in this size range are too small for most immune systems to react to.
A good over the counter brand of limited ingredients diets for cats is made by Natural Balance. These diets are available without a prescription. They offer duck, chicken, salmon and venison mixed with green peas. It’s important to note that these diets are grain free. Grain free foods are not a good choice for every pet because of the risk of associated heart disease in some animals. A hydrolyzed diet may be prescribed by your veterinarian instead. Some examples are Purina’s HA diet and Hills Science Diet Z/D.
Symptomatic treatment for feline miliary dermatitis
The underlying trigger for the multiple scabs on a cat may not be easy to find. If non-allergic diseases are excluded, then symptomatic treatment may be initiated with drugs that control itch. These choices can include immune modifying drugs like steroids and cyclosporine, and antihistamines and fatty acids like fish oil.
Steroids are highly effective in most cats with environmental allergies (atopy). Cats are usually given prednisolone orally at 1mg/kg/day and this is gradually tapered.
Some of my feline patients have a seasonal recurrence of their miliary dermatitis. A few will have a characteristic eruption that always occurs in one spot (usually in front of the ears or on the back of the neck/between the shoulders). These lesions typically respond quickly to the application of a steroid.
What you can give your cat at home to treat skin allergies
For local spots of irritation a spot of topical spray that contains a steroid may be all that’s needed. I typically prescribe a spray which contains an antibiotic and a potent steroid called betamethasone which is over 100x more potent than the hydrocortisone. However, zymox does carry a 1% hydrocortisone spray that has some good reviews for treating cats with allergic skin disease if applied once daily for about a week. 1% hydrocortisone is the most potent steroid available in over the counter products.
Here’s an example of a positive review of someone who had good success treating her cat with zymox spray for miliary dermatitis:
This stuff is a game changer! I have a semi-feral FIV positive senior cat who lives outdoors. Despite giving him flea meds, he gets terrible flea allergies which he’ll pick at until it becomes a bacterial infection. The vet gave him a steroid shot, but shortly after I noticed he had bloody scabs ALL OVER his body. Poor thing must have been so uncomfortable. I ordered this spray due to the higher amount of hydrocortisone in it. It’s now day 8 of giving him this spray (1x daily) and his scabs are almost 100% gone!!!! And he doesn’t even fight me when I do it, probably because he knows it gives him such relief from the itch. Truly a miracle in a bottle and much cheaper and more effective than the vet.
Cats tend to respond better to antihistamines than dogs and it can also be helpful for itchy skin. A good choice for cats is chlorpheniramine: give 2-4mg 1-2 times per day in a cat. While antihistamines stand a good chance to be helpful to a cat, it can be challenging for a lot of owners to give their cat a tablet on a regular basis .
Essental fatty acid supplements for cats
Essential fatty acid supplementation (EFA) is often used for anti-inflammatory effects and hyper -sensitivity disorders. The usual dose given is 50 mg/kg of EFA daily composed of EPA and DHA. A good source of EPA and DHA is in marine fish oil. A common dose given to a cat is a 250mg capsule daily of fish oil or 250mg of EPA and DHA in a fish oil that is pumped onto food. If the fish oil comes as a capsule it can be pricked with a needle and emptied onto their food.
Another good source of EFA’s are in a pipette applied directly to the skin weekly. Dermoscent makes a spot on product that helps to restore the skin’s natural barrier and improve dry skin and itchiness. It is called Dermoscent Essential 6 Spot-on
There are a lot great reviews of this product on Amazon including this one:
My cat’s fur never looked better! …i managed to get my cat off STEROIDS that were controlling her skin allergies for over a year! Finally our vet recommended these drops and she has never been softer, better looking kitty plus she barely sheds. Her fur got back the shine and quality.I cannot recommend this enough especially if your cat has skin itchy allergy/problem.. maybe all you need to use for her is this..
Don’t forget about ringworm as a possible cause for hair loss and miliary dermatitis in your cat
Occasionally ringworm can present in a cat with localized or diffuse scabby lesions. If cats are living together and if a person in the home develops lesions on their skin it could be a sign of ringworm carried by one of the cats. The cat in the picture below has some areas of hair loss with some raised scabbed bumps around the face. This is due to a fungal infection of the skin called ringworm. Ringworm is spread between infected animals via fungal spores that are shed in their dander. Not all cats with ringworm show symptoms. If one cat in the home is diagnosed with ringworm then all the cats in the home need to be treated.
Treating ringworm in cats
Treatment for ringworm requires a lengthy course of oral antifungal medication and topical treatment with special lime sulfur shampoo. The FDA has approved an antifungal medication called Itrafungol for the treatment of ringworm in cats. It can be given as a pulsed dose program every other week for 5 weeks. While oral therapy is less messy, topical therapy is very important as it can quickly reduce the risk of continued transmission of fungal spores in the environment. The quickest means to treating ringworm is by coming to oral and topical therapies.
Ringworm is tested by culturing a sample of hair or collecting debris from affected lessons and growing them on special media for 3 weeks. Ringworm is treated until at least two consecutive negative cultures are returned. The first culture is generally submitted no sooner than 2 weeks after initiating therapy. To initially diagnose ringworm your veterinarian can submit a sample for PCR which comes back within just a few days.
Ringworm can be treated with lime sulfur dips only. Dips are performed twice a week until at least 3 consecutive negative cultures are obtained. If dipping your cat at home, be sure to follow the recommended dilution for the shampoo. The University of Wisconsin’s Veterinary School has a useful online guidebook to treating ringworm.
Immune mediated skin disease (pemphigus foliaceus) as a cause for hair loss with scabs in cats
Pemphigus foliaceus is an immune mediated disease that can cause miliary dermatitis. Typical changes are thick adherent yellowish crusts along the insides of the ear tips and sometimes swelling and crusting of the nail beds. Pemphigus is caused by immune deposits at the connections between skin cells. This causes these skin cells to lift away from their connections and form pustules and scabs. Pemphigus is treated with immunosuppressants like steroids which help reduce the immune deposits in the skin.
Pemphigus is ideally diagnosed by biopsying the skin but sometimes can be diagnosed with a simple impression of the skin with a glass slide to collect skin cells. If your veterinarian sees evidence of acantholytic keratinocytes on the slide, it is very likely pemphigus. Acantholysis is evidence of skin cells that have lost their adhesions to surrounding skin cells. These abnormal skin cells look uncharacteristically large with rounded edges on the slide.
Another immune modulating drug that can be very effective in cats with severe allergies or immune-mediated skin disease is a drug called cyclosporine. This drug inhibits a cytokine which activates a key inflammatory pathway. This medicine comes as a liquid (Atopica) and is given daily for about 4-6 weeks and then tapered to the lowest effective dose.
Patches of hair loss and punctate small scabs and itchy skin are hallmarks of a unique skin reaction seen only in cats: Miliary dermatitis. While there are many potential causes of miliary dermatitis in cats, by far the most common triggers are due to allergies. It is almost always recommended to put a cat with recurrent miliary dermatitis on a hypoallergenic diet and routine ectoparasite control (flea/mite monthly top spot application) to help control for those variables. Depending on the severity of the skin reaction, your veterinarian may choose to look for other causes of the skin reaction with skin samples (impression samples or even skin biopsies) and sometimes skin cultures.
