Why Are There Scabs On My Cat’s Back?

What is feline miliary dermatitis?

Because cat skin allergies have so many possible causes and provocations, what we refer to as miliary dermatitis goes by a number of names. Ones you may have heard include the feline acne, feline eczema, along with the colorful and nonspecific "blotch," the highly descriptive "scabby cat disease," as well as flea allergy dermatitis. This last term describes the most common cause of scabs covering a cat's back and the one that confounds most cat owners.

There are a wide variety of causes of miliary dermatitis in cats,

external and internal, but they express themselves in the same ways and with the same set of symptoms. We've mentioned cat scabs, but these are only the most obvious and telling signs. Prior to the appearance of scabs, you may notice your cat begin a regimen of outrageously excessive self-grooming. Now, cats spend nearly half their waking life licking and cleaning themselves, so is there a distinction?

When dermatitis is involved, skin inflammation’s first yield is an itchy rash,

which can be difficult to perceive, depending on the length of a cat's coat. One sure symptom of miliary dermatitis is repeated attention to licking, scratching, or biting a specific and localized area. As the rash spreads, a cat may not only groom obsessively, but begin balding at those sites. Areas typically affected are the neck and the spot where the tail meets the trunk.

What causes dermatitis in cats?

Scabs lining a cat's back, neck, and the base of the tail, then, are not caused by the allergy itself, but by the cat's singleminded focus on getting relief from the allergy. The more intently a cat scratches, licks, and bites at himself, and the longer the condition progresses, the more scabs will form. Scratching at scabs clears a path for further, secondary infections by usually harmless bacteria that live on cats.

Now, there are rashes and lesions present prior to the cat’s self-grooming traumas,

and these arise from a number of possible agents. Things that can cause these allergic reactions and start the ball rolling toward a scab-covered cat include:

Materials in new bedding, carpets, rugs, or other home furnishings

An ingredient or ingredients in cat food

Seasonal allergens, like pollen

Common household chemicals, including cat shampoo

Mites, such as a sudden proliferation of ear mites or Cheyletiella (walking dandruff)

Fleas and flea bites

By far, the most common cause of miliary dermatitis in cats and the scabs that accompany the condition is the bite of a flea.

Flea allergy dermatitis in cats

Since a huge number of domestic cats spend most of their time indoors, we can anticipate the cries of protest and alarm. How can a cat express allergic reactions to fleas if she has no fleas? If the home is regularly cleaned? If the cat is taking preventative medication or wears a flea collar? For cats with flea allergies, especially those with sensitive skin, or younger cats and kittens with still-developing immune systems, the distinction between having fleas and being bitten by a flea is inconsequential.

All cats, indoor cats in particular, are fastidious groomers.

Their rigorous cleaning routines mean that even cats who encounter fleas occasionally will not necessarily have them crawling and bouncing all over her body. In other words, a cat does not need to "have fleas," per se, to experience the ill effects of a bite. If a cat gets out of the house during the warmer parts of the year when fleas are in abundance, even a brief period of Caturday excitement can expose her to fleas.

For cats with sensitive skin, indoor cats with limited exposure to the natural world,

or those whose homes are kept so immaculate that they don't even wear flea collars, the saliva from a single flea bite is sufficient to provoke an allergic reaction. This condition, called flea bite hypersensitivity, is an increasingly common, if not the leading, cause of skin allergies among cats and dogs. It is also the first step toward the formation of millet-shaped scabs on cat backs, necks, and tails.

Treating cat dermatitis

Diagnosing miliary dermatitis is fairly easy for a practiced veterinarian. The placement of the rash, lesions, or scabs depending on how far advanced the problem is gives a vet a clearer idea of the true source of the allergic reaction and a good start to a reliable method of treatment. Determining the precise source of your cat's skin allergy is key.

For cats who already have sores from excessive grooming where flea bites are at fault,

knowing that they have a flea allergy is no condemnation of you as a cat owner or your home cleanliness. Cortisone injections can help alleviate persistent itching, and, if necessary, antibiotics may be prescribed to treat existing wounds.

Going forward with knowledge of the cat’s allergy, preventative measures may be counseled by the vet.

Indoor cats who like to venture outdoors may be cautioned against it, or regular use of anti-flea prophylactics may be recommended. Implementing prevention strategies might see you and your cat changing your normal routine, but being consistent with the new routine will ensure your cat doesn't suffer from recurrent bouts of miliary dermatitis.

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