Itchy Kitty Syndrome 101 (Part 1): The Allergic Cat

Patty Khuly, DVM
Updated: February 02, 2021
Published: October 31, 2006
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Does your beloved cat spend an inordinate amount of time grooming?…the same spot over and over again? What’s up with that?

Some cats just groom a lot — not to worry — unless that one spot starts to look like the back of your husband’s head, all fuzzy with thinning hair (you know the look). In some severe cases it even appears that the skin is being licked off as well — because it is.

A few cats even start to bite or gnaw at themselves in dog-like fashion. This is bad. This is a very unhappy kitty, as any self-respecting cat would be if relegated to unseemly and seriously uncomfortable canine behavior.

Simple scratching is common, especially around the ears. A look-see is required if you think your kitty spends too much time scratching there—or anywhere. If you see a lot of gunky black stuff in there that resembles motor oil more than it does earwax (and seems just about as difficult to clean) your kitty needs a vet check. If the black gunk flakes and your kitty can’t help but scratch non-stop then you might even have an ear mite problem.

Outdoor cats are the ones most likely to have those pesky ear mites — not to mention the fleas we all dread for their indiscriminate biting behavior (those of you that scratch at your ankles when reliving this memory know exactly what I’m talking about). But neither fleas nor ear mites are the most likely cause of the itchy kitty syndrome I’m discussing today.

If your cat is one of these over-groomers, no external parasite is likely to be the sole cause of his problem. More than likely, you’re looking at one of those complex, poorly understood allergy-meets-brain-chemistry disorders cats are famous for. Again, these mysterious beasties keep us guessing.

First things first: If you think your cat is over-grooming or itchy — see your vet. But when your vet doesn’t have thirty minutes to describe in excruciating detail the complexity of what might be going on — here’s a helpful primer that might help you ask the right questions and get moving on fixing the problem (if it’s indeed fixable).

Let’s tackle the allergy issue first. Like us, cats can have allergies to a wide variety of environmental culprits. Although most people want to run and change the litter or rip out their lawn, no one change is likely to make a bit of difference. Cats with allergies to just one thing are extremely rare. Usually, they’re allergic to a whole bunch of things — and not typically to the inorganic stuff found in most cat litters.

The most common allergens fall into one of four major categories:

1. Insects — the pesky six-leggers led by the king of integumentary evildoers: the flea

2. Inhalants — things they inhale like grasses, pollens, dust, molds, etc.

3. Foods — either a protein source (beef, chicken, fish, pork, eggs, etc.), or a carbohydrate (corn, wheat, potatoes, etc.)

4. Contacts — things they rub up against that cause local inflammation (by far the least common type of allergy, believe it or not)

So how do you know if your kitty has an allergy to one of these? Although there are a few ways to find out, unfortunately none of them are pleasant.

Let’s say this skin condition has all of the hallmarks of an allergy and we’ve ruled out a flea infestation and a bunch of other skin problems (like fungal infections and lice or fur mites). The first step in most vet hospitals usually involves an injection of a steroid or a short course of steroid pills. Most vets try this tack first because (1) it's easy; (2) it's cheap; (3) it might actually help; and (4) if it does help you can be pretty sure there’s an allergy there somewhere, so it’s helped us diagnose the problem.

So after the magic shot or happy pills where do we go? Assuming it’s an allergy we’re dealing with, the problem will rear its ugly head sooner or later. If the problem only pops up once a year or every few months then we probably keep doing the same thing over and over again. (Yes, I know steroids are evil but in this minimal version of its use it actually solves everyone’s problems in a relatively innocuous way.)

Now, if the problem keeps on keeping on week after week or month after month then we have to move along to the next battery of tests. We certainly want to check your cat’s blood for evidence of any untoward issues that might predispose her to skin problems (something I would have offered in step one) then we might consider either an allergy screen or a food trial.

Usually the food trial comes first (it’s cheaper and, usually, easier): This involves either getting your kitty to eat an expensive prescription diet or learning to cook for your cat. Problem is, she has to eat just that one food for the entire time of the trial (as long as three months). That means no treats, no sneaks, and no lizards, songbirds, or mice.

While the food trial may not solve the problem it often helps somewhat. Perhaps it helps enough to make the problem bearable? That’s for kitty’s owner to decide.

Next up, the allergy screen. Although this test is best done by a veterinary dermatologist, I find most of my clients balk at the $700 bill for the skin tests that constitute a dermatologist’s typical screen (along with the huge patch of shaved fur). Most owners prefer to have me draw some blood and send it to a lab instead. At $350 it’s not a bargain but it’s an acceptable fee for many frustrated owners.

A good allergy screen will often tell us exactly what a cat’s body is over-responding to in her environment, but no test is 100 percent on target every time. The risk here is that we don’t end up finding as much of a problem in kitty’s blood as what she’s displaying at home when engaged in her extreme licking activity. If we don’t come up with a problem we can’t attempt to find a solution (usually a course of allergy vaccines or an oral medication called Atopica). 

It’s at this point that we start talking about (1) sending you and your itchy kitty to a dermatologist (I usually offer this long before the serious complexity sets in); or (2) moving beyond the body’s largest organ system (the skin) to the most complicated one: the brain. Stay tuned for Part 2!

Image: aaaa itchies by Bright Green Pants