12 min

Does My Cat Have Allergies? Signs, Diagnosis & Treatments

Does your cat have allergies? An in-depth look at types of allergies in cats (flea, environmental, food), their symptoms, diagnoses, and treatments.

Aly Walansky

Updated December 14, 2022 • Published April 02, 2021

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Does My Cat Have Allergies? Signs, Diagnosis & Treatments

Has Fluffy been wheezing? Does she seem to have watery eyes or is she scratching more than usual? Just as with a person, a cat can have allergies, and their reactions can reveal themselves in many different ways. If your cat is breathing funny, has watery eyes or a runny nose, they may have allergies. The same may be true too if they have itchy skin or an upset stomach. Figuring out the type of the allergy — whether it's flea, environmental, or food-related — and the reason for it is the first step to finding out how to make your kitty feel better.

We're going to take a look at the different types of allergies in cats, signs your cat may have those different allergies, how to diagnose which allergy it is, and finally, how to treat those allergies. It may be difficult to determine which type of allergy your cat may have, in which case, it's a good idea to talk to a vet.

The different types of cat allergies

If your cat is suffering from an allergy, it will generally fall within three categories: flea bites, environmental, or food. 

  1. Flea Allergies In Cats

    • Signs & Symptoms

    • Diagnosis

    • Treatments

  2. Environmental Allergies In Cats

    • Signs & Symptoms

    • Diagnosis

    • Treatments

  3. Food Allergies In Cats

    • Signs & Symptoms

    • Diagnosis

    • Treatments

Flea allergies in cats

Is your cat scratching more than normal? Can you see brown flecks of dirt concentrated in areas around the ear and neck? Your cat may have fleas and, unfortunately cats are very good at hiding it. This common parasite doesn't just affect outdoor cats and should be treated quickly.

Signs your cat has flea allergies

The most common sign of flea bite allergy in cats is itching and scratching along the head and neck. “The itching and scratching will result in fur loss, redness of the skin, open sores, and scabs,” says Dr. Burch. Lesions can also occur along the rump, back, flank, and tail.

Other signs your cat has flea allergies include:

  • Frequent scratching

  • Excessive grooming

  • Fur loss

  • Flea dirt/ brown specks on fur

  • Open sores, lesions, and scabs

  • Lethargy

  • Pale gums

  • Restless/ anxious behavior

How to diagnose flea allergies in cats

If flea bite allergy is to progress without treatment, the lesions can spread over the body and lead to more chronic skin changes, says Dr. Burch. These changes can include darkening of the skin and elephant skin or lichenification. Obviously, you want to avoid this! First step is diagnosing fleas, then it's treating.

In order to confirm your cat has fleas, you'll need to identify them on their person. Check problem areas for fleas like the stomach, tail, neck, or behind the ears. Fleas are small, brown, and wingless, typically ranging from 0.039 to 0.13 inch (0.1 to 0.32 cm). Fleas may not always be immediately visible, so if you identify the flea dirt, it is safe to begin flea treatments on your cat.

How to treat your cat for flea allergies

Cats with flea bite allergies need treatment to remove any fleas from the individual and their environment, including any additional pets. All animals in the household need to be on long-term flea prevention.

Find all the areas of the house that the fleas may be hiding. “The areas you have identified as flea hot spots will need to be cleaned two to three times a week,” says Dr. Burch. Vacuum furniture and remove cushions to reach all of the dark crevices since the larvae want a dark place to hide. After vacuuming, empty the contents obtained immediately from the house. Wash bedding that can go into the washing machine on a hot water cycle. You can also add a small amount of bleach to the wash to help destroy the flea's immature stages.  

“The first environment to treat is indoors,” says Dr. Burch. “All rooms of the house need two treatments, one month apart with an adulticide and insect growth regulator product. If using bombs, only use one per room and ensure all pets are evacuated from this area until completely dry,” says Dr. Burch. The following environment is outside. When treating the outside environment, concentrate on kennel areas, your cat's favorite sleeping spot, or shaded areas. “Thankfully flea eggs and larvae do not survive extended periods of full sun, especially in the summer,” says Dr. Burch.

Environmental allergies in cats

Have you recently changed products you use on or around your cat? “Contact allergy, also known as atopy or contact dermatitis, is a reaction to an environmental source,” says Dr. Michelle Burch DVM from Safe Hounds Pet Insurance. This can be anything from pollen, dust mites, molds, shampoos, sprays, to medications.

Signs your cat has environmental allergies

Environmental allergies often appear as contact allergies, like dermatitis. This one is easily recognizable by just giving your kitty a good look and seeing if anything appears off. “Cats with early signs of contact allergy will have redness and papules (zits) along the belly, anus, armpits, ears, tail, between the toes, and around the mouth,” says Dr. Burch.

Other signs your cat has environmental allergies include:

  • Scratching

  • Overgrooming

  • Licking/biting paws

  • Red or watery eyes

  • Red patches of skin

  • Papules or zits

Read More: Does Your Cat Have Dry Skin? How To Help

How to diagnose environmental allergies in cats

With chronic signs, skin lesions can get worse and start crusting, and even lead to hair loss, and thickening of the skin. Figuring out if your cat has an allergy, and what that allergy is, may take some time. First you may want to visit your veterinarian and try a patch test to discover what your cat is allergic to — and if it can be avoided.

To patch test your cat, a small amount of a suspected allergen is applied to the skin and monitored for a reaction. “Test kits are human-based but do have over 300 allergens available for testing. Caution does need to be used as some cats can have a false positive reaction meaning they genuinely are not allergic to that specific allergen but have a response,” says Dr. Burch.

How to treat environmental allergies in cats

The best treatment option is to remove the item causing the issue from the environment. “This treatment option is not always feasible, especially if dealing with airborne plant pollen,” says Dr. Burch. Frequent bathing can help remove the allergen from their fur, but your cat may not be happy with the bathing. 

"Topical medication therapy may help resolve skin lesions but can be challenging to keep on your cat," says Dr. Burch. Cats are fastidious groomers and can quickly remove topical products after application resulting in minimized benefits. "Systemic therapy is also started to minimize the immune response your cat is having to the allergen,” says Dr. Burch. Your veterinarian may prescribe a steroid, cyclosporine, or pentoxifylline.

Food allergies in cats

Have you recently changed your kitty’s food? A food allergy in a cat is a response to a specific food. “Food intolerance does not stimulate the immune system but will cause a physiological reaction to the food (vomiting, diarrhea),” says Dr. Burch. The most common food allergy sources in cats include beef, fish, chicken, wheat, corn, dairy, and lamb (in order of most reactive). 

Signs your cat has food allergies

Cats with food allergies can have all sorts of reactions, but usually it’s a skin issue or an upset tummy. “Up to 77% of cats with food allergies have a skin response,” says Dr. Burch. “A cutaneous reaction's symptoms can include itching around the face, head, and neck with or without lesions.” 

Tummy issues associated with a food allergy may or may not accompany skin symptoms. “In cats, the signs of a food allergy affecting the intestinal system include vomiting, painful belly, diarrhea, drooling, and flatulence. Food allergies can also be a factor with inflammatory bowel disease for some cats,” says Dr. Burch.

Other signs your cat has food allergies include:

  • Itchy paws, belly, and ears

  • Skin lesions

  • Hair loss

  • Redness of the skin

  • Open sores and scabs.

  • Upset stomach

  • Diarrhea

  • Vomiting

How to diagnose food allergies in cats

Much like with a person, the best strategy for diagnosing food allergies in cats is through an elimination diet. This trial should last for six to 12 weeks. “An elimination diet for cats can include either a hydrolyzed diet or a limited ingredient diet with a single protein and single carbohydrate source. The gold standard to complete a food trial is to then perform a food challenge by adding in new ingredients and monitoring for reaction,” says Dr. Burch.

Talk to a vet about your cat's nutritional needs so they can help you come up with a safe and healthy diet.

How to treat food allergies in cats

Just don’t feed them the offending food item. This may mean a prescription diet long-term, home-cooked meals or finding a commercial diet that does not have the ingredient,” says Dr. Burch.

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