Allergies are a deceptively common ailment in household cats; it’s estimated that one in five cats have allergies. Cats can develop allergies to many different things over time. These may include outdoor allergens like mold or pollen, household substances like perfumes and cleaners and even foods like wheat or chicken.

Unfortunately, since cats interact with so many substances on a day-to-day basis, it can be very challenging to pinpoint what exactly is causing its allergic reaction. While the timing and type of reaction may help you narrow down whether the allergy is environmental- or food-related, you’ll need to work with an experienced veterinarian to determine the specific root of your cat’s allergy symptoms.

Although allergies are relatively common in pets, many pet owners are unaware of how allergy testing actually works. Here’s what you can expect if you bring your cat in to be tested for allergies.

Checking for fleas

One of the main causes of allergies is actually an infestation of fleas. Some cats can have an allergy response to flea saliva, resulting in itchiness and discomfort.

Because of this, many vets start the allergy testing process by verifying that the pet does not have fleas. Fleas are relatively easy to identify because of the “flea dirt�? they leave behind and their physical presence.

If it’s found that your cat does have fleas, your vet will administer treatment to eradicate them, and your pet’s allergic reactions will hopefully be resolved. If the allergies continue after flea treatment, more testing may need to be completed.

Testing for environmental allergies

One of the main ways to diagnose environmental allergies in cats is through a blood test called the radioallergosorbent test (RAST). This test measures levels of IgE, a specific type of immunoglobin in your cat’s immune system.

Through the RAST testing, your vet may be able to determine whether your cat has allergies and what types of things it might be allergic to. The blood test usually takes around a week to get completes results but is generally accurate. Additionally, the pet will not need to be shaved and can remain on anti-itch medications or supplements to treat symptoms.

Unfortunately, blood tests are not usually reliable when it comes to food allergy testing, so other methods may be required if food allergies are suspected.

Another method of testing for environmental allergies is the intradermal skin test, or skin prick. During this test, an area of your cat’s fur will need to be shaved to allow for injections and examination of the skin.

Specific allergens are injected in very small amounts under your cat’s skin. After the injections, your vet will examine each injection to see which produced a localized allergic response (typically redness, inflammation or a hive). Your pet’s skin will not react to substances that it is not allergic to.

Skin testing is another good way to determine the severity of particular allergies. The benefit of this test is that results appear immediately. Unfortunately, your pet will need to stop taking anti-itch medications, which may be uncomfortable for it.

Testing for food allergies

The way vets determine if a cat has an allergy to food is a little different from the environmental allergy testing process.

A relatively new concept is saliva testing. During this test, the vet will test a saliva sample from your cat, checking IgA and IgM antibody levels. These immunoglobins are mainly found in the digestive tract, so they may be a better indicator of food allergies than IgE that is tested in a blood test. However, this method is not that wide-spread yet.

The preferred way to test for food allergies is usually food trials. During this process, you must remove your cat from its current diet and switch it to a novel protein and grain (one that it has never eaten before) to see if its symptoms clear. You’ll want to try to find novel ingredients that are more obscure and not commonly found in pet food.

The pet will need to eat this new food exclusively for around eight weeks (meaning no table scraps or treats!). If your pet’s allergy symptoms clear, it might have an allergy to its food.

Next, you’ll introduce ingredients back into your cat’s diet one at a time, watching for symptoms of allergic reactions. If your cat reacts after adding a particular ingredient, you’ve found an allergen you’ll need to avoid in the future!

One food change every four weeks is usually recommended to be sure that symptoms manifest and are noticed if an allergy is present, as well as to avoid upsetting your cat’s stomach with too many changes too quickly.

Getting to the bottom of your cat’s allergies can be a frustrating process, but ultimately, diagnosing specific allergens is important to help minimize contact and help your cat live a comfortable, allergy-free life.