Tests for Cat Allergies

Pet allergies are a common ailment among people who suffer from allergies, and allergic reactions to cats are no exception. Although for some people their cat allergy is obvious--resulting in an itchy nose and eyes, sneezing, a stuffed-up nose and inflammation any time they are around a cat--for others, testing might need to be done to confirm the allergy.

Causes

• If you are allergic to a cat, it is usually the cat's dander rather than its hair that causes the allergic reaction. Dander is made up of dead skin cells shed by the animal. Contact with a cat's saliva or urine can also cause an allergic reaction in some people. All three allergens can be carried on the cat's hair, which leads to the common misconception that it is the hair causing the allergy.

  When you develops an allergy to something, the immune system is overreacting to otherwise harmless substances, such as plant pollen, foods or in this case, cats.

Types of Tests

• There are several ways a doctor can test a person for an allergy. Doctors will usually start by doing a physical examination and then move on to doing one of three skin tests or blood tests.

Examination

• When a doctor examines someone for a possible allergy to cats, she will mostly likely ask you questions about the your exposure to cats and your symptoms when around them. From there, the doctor will do a physical examination of the areas most often affected by allergies, the skin, eyes, nose, ears and throat, by looking for inflammation, sinus drainage, itching, rashes or other symptoms.

  After the examination, the doctor might order further testing to determine if you are definitely allergic to cats or what other allergens you might be having reactions to.

Skin Tests

• There are three types of skin tests: the scratch test, the intradermal test and the patch test. All three tests are designed to test the body's response to specific allergens by looking for a reaction on the skin.

  -Scratch Test: This test is usually done on the forearm or sometimes the upper back. The scratch test involves using a plastic pricking device to lightly pierce the skin. At each scratch small drops of certain allergen extracts are applied. The extracts are left on the skin for 15 minutes to test your reaction. If you are allergic to cats, the spot where the cat allergens were applied will be itchy and irritated.

  -Intradermal Test: The intradermal test is similar to the scratch test except that instead of applying the allergen extracts to scratches on the skin's surface, the extracts are injected under the skin. The doctor will look for a reaction within about 15 minutes.

  -Patch Test: Another type of skin testing involves using a patch, which has an allergen applied to it. The patch is then placed on the skin for about 48 hours and then you are examined for a reaction.

Blood Tests

• Blood tests are sometimes performed when a person has a skin condition or is taking a medication that could make a skin test unreliable. There are two types of blood tests, the radioallergosorbent test (RAST) and the enzyme-linked immunosorbent assay (ELISA) test.

  For each test, blood is taken and screened for certain antibodies that will indicate an allergic reaction to specific allergens. If you have high levels of antibodies to an animal allergen, such as cat dander, you are probably allergic to cats.