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What’s Up With My Cat’s Skin?

Everything you need to know about cat allergies, according to three veterinary dermatologists.

by Tim Barribeau
November 28, 2021
Gray and white striped cat is scratching his ear

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It’s uniquely hard to see a pet suffer from a horrible itch. Unlike with humans, you can’t explain what’s happening to them, and it’s hard to ask what they’ve been doing that might have set it off. With cats it’s especially difficult, since sometimes the first thing you’ll notice is a scary looking mass of scabs. Thankfully, most allergies are rarer in cats than humans, and are manageable with long-term treatment. If you’re worried your cat is having an allergic reaction, here’s what to look for, and what treatment might end up looking like.

Allergic reactions in cats most often show up as scabby skin, crusty eyes and face, breathing problems, or unusual swelling. If your pet has any of these issues, allergies might be to blame. But first things first: All diagnoses and treatment should be done in conjunction with your vet. Don’t try and undertake a long and complicated medical procedure on your pet without having an expert’s advice — just because you think it’s allergies doesn’t mean it is for sure.

Causes of Skin Allergies in Cats

There are four major causes of allergic reactions in cats: fleas, foods, inhalant/seasonal, and contact — of these, fleas are the most common. A flea allergy is different from your cat just scratching at a flea bite; instead, it’s a reaction that can cause itching across their entire body. As veterinary dermatologist Dr. Millie Rosales, DVM, DACVD, explained to me, tick allergies are by far the most common allergy type she sees — and more than a little preferable to other types, because ticks are directly and easily treatable.

The other three types are closely linked to exposure to the allergen, and it’s generally a matter of treating the symptoms as you can, attempting to keep your cat away from whatever’s setting them off, and potentially seeking long term treatment like immunotherapy.

Symptoms of Cat Allergies

There are a surprising number of symptoms that are often seen with allergic reactions in cats — though it can be tricky to pin down a single symptom as a definitive indicator. As Dr. Erica Hess, DVM, a veterinarian currently completing her residency in dermatology, explained to me, there’s a long list of potential symptoms. Dr. Hess said to look for “scratching (especially around the face/neck), hair loss, inflamed skin, overgrooming (especially the abdomen), skin lesions such as small red bumps (“papules”), pimple-like lesions (“pustules”), excoriations, crusts, lesions affecting the lips or oral cavity, and chin acne.”

Many of the symptoms we associate with allergies in cats come from “atopic dermatitis,” which is like the kitty version of eczema, a.k.a. red and itchy skin. In cats, this presents commonly as “miliary dermatitis” — this is where a cat gets so itchy that they lick and scratch their skin to the point of causing bunches of little scabs to form. If you’ve ever been groomed by your cat, you know how scratchy their tongues can be — now dial that up to 11 as they aggressively lick at one spot over and over to try and relieve the itch, and it makes sense why the skin would break and scab over.

Cats may also show “self-inflicted alopecia”: areas of skin they’ve rendered bald by over-aggressive licking. Dr. Rosales told me that pet owners may have the common misconception that cats licking themselves bald may be due to stress or other behavioral issues, but she explained that’s true for “a very small percent” of cases and “the majority of the time it’s because they have an allergy.” So if your cat is licking themselves to the point of hair loss — get them to a vet.

Allergies can also cause your cat to have mouth ulcers and respiratory issues like coughing, sneezing, or wheezing. Dr. Hess also made sure to add this reminder: “Many of these symptoms can be seen with a number of other conditions, and a thorough patient history along with a complete physical examination by a veterinarian is crucial.”

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Diagnosis of Cat Allergies

Many of the symptoms associated with cat allergies can also be caused by other issues like fungal infections, bacterial infections, or parasites. So if you suspect your pet is having an allergic reaction...talk to your vet. Dr. Rosales pointed out that if your cat tests negative for those problems, chances are allergies are the culprit; veterinary dermatologist Dr. Nicole Eckholm, DVM, added that if the skin issues respond positively to steroids, that’s a “slam dunk” sign that it’s allergies. 

Because cats can show allergic reactions a number of different ways, it can be hard to pin down the exact cause. And the site where a cat is having a reaction isn’t as closely linked to what set them off as it is in other animals, like dogs. Like with humans, your vet may give your cat a skin pinprick test where they inject tiny amounts of allergens and see how much your skin bumps — but Dr. Rosales told me that since cats have such thin skin, it may be difficult to test them accurately this way, and a vet may also do a blood test for more information.

It may take a number of attempts for your vet to correctly identify what’s causing the allergic reactions — but it’s a process. Give it time, and work through all the steps so that you can all be sure and treat the issue properly.

Treatment for Cat Allergies

Treatment for a cat’s skin allergies will depend on what’s causing them and should be undertaken with veterinary advice.

Flea Allergy Treatment

For allergies related to fleas, the first step is usually aggressive flea protection for cats. If you’re not already using flea meds, this is the time to introduce them, or if you are, to consider using multiple forms of flea protection to really keep their numbers down. And do a deep flea cleaning of your pet and your home. Just because your cat is indoors only doesn’t mean they can’t get fleas. As Dr. Rosales puts it, “[Fleas] are very sneaky, and they move very fast so they’re really hard to spot.” A small number of fleas can be hard to see, as your cat may be even catching them while grooming, but there may still be enough around to cause the allergic reaction. A flea comb for cats can often be quite effective for those suffering from the pests.

Miliary Dermatitis Treatment

For cats with miliary dermatitis, your best bet is to treat the underlying condition, and with time the skin issues should fade. However, allergies are a lifetime issue — and if you’re not able to cut out the offending allergen, as with tick and food allergies, then you’re looking at long term treatment options. Steroids and cyclosporine are useful in the short term, but as veterinary Dr. Eckholm explained to me, they have long term issues, with the former potentially leading to diabetes and the latter being an immunosuppressant. She told me that immunotherapy is the safest long term treatment option for your pet, and that she’s seen a 70% success rate with it. As she put it, good allergy management still allows your “cat to be a cat” without you attempting to control every single thing they come in contact with.

Though Dr. Eckhorn commented that if you’re doing immunotherapy, you’re in for the long haul. You have to regularly give your cat shots (though many cats have fewer issues with shots than mouth drops or other oral medication), and it can take a year to see success — but for most cats, success does happen, and it prevents allergies from worsening. Dr. Rosales echoed this, explaining that the injections will eventually slow down to just once a month, and she’s seen good success with them. 

You can also help your cat by limiting airborne allergens through regular vacuuming, and running dehumidifiers and air filters. However, as Dr. Eckholm explained, you track pollen in and out with you when you enter and leave a space, so truly keeping your cat away from airborne allergies can be almost impossible.

Food Allergy Treatment

Food-based allergies are a complex enough topic to warrant an entire piece on their own, but suffice to say: Talk to your vet and work on putting together an elimination diet where you can narrow down the allergen and remove it from your pet’s food supply.

Contact Allergy Treatment

Contact allergies are the least common and may come from bedding, collars, skin treatments, or plants your pet comes in contact with. It can be tricky to pin down exactly where the offending item is, but when you do, it’s generally straightforward to prevent your cat from getting in contact with it.

No matter what the cause, dealing with cat allergies is an ongoing process, and something that will most likely be a worry over the life of your cat. Thankfully, with smart treatment and a lot of love, chances are your cat will be just fine.

tim barribeau

Tim Barribeau

Tim Barribeau is a freelance writer, editor, cat dad, and “help your boyfriend buy a suit that actually fits for once” consultant. He was previously the Style and Pets editor at Wirecutter, and has bylines at a bunch of publications that don't exist anymore (and a couple that still do).