7 Common Cat Allergies

By Jennifer Coates, DVM

Allergies are on the rise in people, and nobody is exactly sure why. Maybe it’s because we no longer have to continuously battle parasites and germs, which leaves our immune systems free to overreact to potential allergens. While we don’t know if a similar process might be happening in cats, it is safe to say that feline allergies are big problem for the pets and owners who are affected by them.

Read on to learn about the most common allergies in cats, what the symptoms of these allergies are and how they’re treated.

Many cats have allergies to fleas and become incredibly itchy after being bitten just once or twice. You may not be able to find any evidence of fleas on your cat because cats with flea allergies tend clean themselves very aggressively. Licking, biting or scratching particularly around the neck, thighs, belly, flanks and base of the tail can be signs of a flea allergy in cats.

Long-term use of a flea control medication containing an adulticide that kills adult fleas and an insect growth regulator (IGR) that prevents immature fleas from growing up and reproducing is the best way to manage flea allergies. Never use canine flea medications on cats since they can make cats very sick. Your veterinarian can recommend a suitable product based on your cat’s particular needs.

Cats can also be allergic to indoor allergens like mold, dust, household mites, etc. Indoor allergies are indistinguishable from outdoor allergies, except that the licking, biting and scratching is often year-round rather than seasonal right from the start. Your veterinarian or a veterinary dermatologist can determine if your cat has indoor allergies using an intradermal (skin) or blood test.

To reduce your cat’s exposure to indoor allergens, deal with any mold problems in your home, clean frequently and thoroughly, use air filters, and regularly bathe or wipe your cat’s coat with a damp cloth. Veterinarians can also prescribe fatty acid supplements, anti-histamines, hyposensitization therapy, immunosuppressive drugs and other treatments to help manage symptoms in cats with indoor allergies.

Allergies to particular ingredients in food are another type of feline allergy. Cats with food allergies typically have itchy skin and may also develop recurrent skin or ear infections and have gastrointestinal signs like vomiting, diarrhea and/or increased gassiness. Cats can develop food allergies at any age and whether they have been eating the same food for years or have recently started eating something new.

To diagnose a food allergy, your cat must be fed either a novel ingredient diet (e.g., duck and potato) or a hydrolyzed food (and nothing else but water) for six to eight weeks. If the symptoms disappear during that time, your cat has a food allergy. To treat your cat’s food allergy, you can either continue to feed the food used in the diet trial or reintroduce standard ingredients one at a time to determine exactly what they are allergic to. While some food allergic cats can eat hypoallergenic diets that are available over-the-counter, others have to eat the more strictly regulated foods that are only available through veterinarians.

Human allergies to plastic have been documented in scientific literature, and while similar studies have not been done in cats, anecdotal reports seem to link eating and drinking from plastic bowls with a condition called feline chin acne that may be allergy related. Cats with chin acne have solid or pus-filled bumps around their chins. 

If you think your cat might be allergic to plastic, try switching to ceramic or glass plates or bowls, but make sure you clean them regularly since the bacteria-laden slime that can form on the bottom is another possible trigger for chin acne.

Some cats are very sensitive to the perfumes that are frequently added to cat litters, cleaning products, air sprays, carpet powders, dryer cloths, etc. If you find that your cat is sneezing or becoming itchy after contact with these types of products or is trying to avoid perfumed areas altogether, an allergic or irritant-type reaction may be to blame. Try switching to unscented products and see if your cat’s symptoms disappear.

Drug allergies are relatively rare in cats, but any individual can have an adverse reaction to a particular drug without warning. Symptoms vary but can include itching, hives, fever, vomiting, hair loss (topical products) and in severe cases anaphylaxis, which may cause difficulty breathing, collapse, seizures and death. If you suspect that your cat is reacting poorly to a medication or have any other concerns about your cat’s health, call your veterinarian immediately.