These 4 Signs Mean Your Cat Might Have Allergies

Here's how you'll know.

cat allergy signs

Your cat’s started randomly itching like crazy, which is totally freaking you out.

Could it be allergies, or something else?

According to Dr. Ruth Lee, a veterinarian at the Veterinary Care Group of Forest Hills in New York City, there are some common signs that might indicate your cat has allergies.

“The most common cat allergy symptoms are skin/coat issues (rashes, hair loss, ear infections) and itchiness,” Dr. Lee told The Dodo.

Here’s a closer look at these symptoms — and what you should do if you suspect your cat is having an allergic reaction.


Itchiness (aka pruritus) is the sensation that encourages the urge to scratch — and it’s one of the most common signs of allergies in cats.

To relieve his itchy skin, you might notice your cat grooming himself a lot more than normal.

Or, you might not. Some cats are known to be secret groomers and will self-groom excessively when they’re alone.

Even if he’s grooming in secret, you might notice bald spots appearing on your cat, which might mean he’s been licking himself more than he should.

Hair loss

The most common reason for hair loss in cats is allergies, and it’s no wonder. An itchy cat will easily lick and chew himself bald to try to get relief — which is why it’s so important to provide allergy treatment ASAP.


Skin rashes (aka hives) appear as red, swollen patches of skin on your cat, and are usually a dead giveaway that your cat is having an allergic reaction — especially when paired with other allergy symptoms.

Hives are a very characteristic symptom of an allergic-type reaction,” Dr. Ursula Oberkirchner, a veterinary dermatologist and owner of Advanced Veterinary Dermatology in Florida, told The Dodo.

Rashes on your cat can even be accompanied by other scary symptoms like troubled breathing, vomiting and diarrhea (which can mean something more serious is going on), so be sure to watch your cat closely if you see hives on him, and get him to a vet ASAP.

Ear infections

An ear infection from yeast is a common side effect of cats with allergies. If this happens, you might see redness on your cat’s ear flap, black or yellow discharge and a lot of itching around the area.

Diagnosing allergies in your cat

If you notice one or more of the above signs (or any other sudden change in your cat’s appearance or behavior), you should definitely take your cat to his vet, who will be able to give him a proper diagnosis.

“[It’s] important to rule out other conditions that can look like allergies/complicate allergies, as well as find out what exactly your cat is allergic to (fleas vs. environmental [triggers] vs. food vs. contact allergy),” Dr. Lee said.

Keep in mind that diagnosing allergies in cats isn’t exactly a straightforward process, though.

“Accurately diagnosing allergies in our pets often takes several steps and various tests,” Dr. Lee said. “Patience is the key to coming to a full conclusion.”

To start, your vet might recommend a full workup, as well as parasite treatments to rule out the possibility of flea allergies.

This “may be followed by a strict six- to eight-week prescription hypoallergenic food trial,” Dr. Lee said, which is essential to rule out food allergies. A food trial basically involves putting your cat on a very reduced diet to eliminate potential allergens, and then slowly introducing foods back in to find out what the trigger was.

“If environmental allergies are suspected, your veterinarian may discuss supportive anti-itch treatment if signs in our cats are mild to moderate,” Dr. Lee said. “However, if severe enough, and if owners are committed, your veterinarian will recommend intradermal skin allergy testing to find out what environmental allergies your cat/dog has and tailor a custom allergy vaccine to help make your pet's allergy symptoms more manageable.”

Allergy vaccines (aka immunotherapy) are a long-term commitment, because it can take about seven months or so to see a response in cats. But it’s the only way to treat underlying allergies for good, instead of just treating the symptoms.

There are other methods of reducing allergy symptoms in your cat. Prescription medication, like Atopica, is often used, and sometimes steroids are recommended if the reaction is really severe.

If your cat’s allergies are super mild, your vet might suggest an over-the-counter antihistamine. The most common antihistamine used for cats is chlorpheniramine,” Dr. Lee said.

Try chlorpheniramine tabs for cats from Amazon for $3.89

If you think your cat has an allergy, your best bet is to bring him to the veterinarian. They can help find out what’s causing your cat’s symptoms and how to get him help in the quickest way possible.

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