Cat allergy

What it is

Cat allergy is a reaction to proteins that cats make, not to their fur. People react to allergens in saliva, dander (skin flakes) and urine.² Fur collects dander, and it can also carry dust mites, mold and pollen.⁵

The main cat allergen is called Fel d 1. Antibodies to it are found in more than 80 to 95% of people who are allergic to cats.¹ Fel d 1 is found in cats’ saliva, anal glands, skin glands, skin and fur, and the oil-making (sebaceous) glands of the skin are now thought to be its main source.¹ Male cats make more Fel d 1 than females, and neutered males make less than intact males.¹

Pet allergy is common. The AAFA says cat and dog allergies affect 10 to 20% of people worldwide.⁵ Among people with asthma, the AAAAI says as many as one in five may be allergic to pets.³

Symptoms it causes

Cat allergen can cause symptoms when it is breathed in or gets into the eyes or onto the skin.⁵ Symptoms include sneezing, a runny or stuffy nose, and watery, red or itchy eyes, and some people cough, wheeze, feel short of breath or have chest tightness.⁴ A scratch or lick can cause redness, itching or hives on the skin.⁵

Symptoms can start within minutes in very sensitive people.⁴ When allergen levels are low, symptoms may not appear until after several days of contact.⁵ In people with asthma, a pet allergy can trigger an asthma attack, and the AAFA says an asthma episode can begin within 15 to 30 minutes of breathing in the allergen.⁵

Where it’s found

Fel d 1 gets into the air easily and stays in the indoor environment.¹ Once stirred up, cat allergen can stay in the air of a room for at least 30 minutes.⁴

Cat allergen is especially sticky, and people carry it on their clothing into homes, classrooms and workplaces where no cat has lived.⁵ Researchers have found Fel d 1 in homes without cats and in classrooms, cars, allergists’ offices and shopping centers.¹ Pet allergen can collect on furniture and other surfaces and stay at high levels for several months. The AAFA says it can cause symptoms up to 6 months after the animal is gone, especially cat allergen.⁵

No breed has been shown to be allergen-free. The ACAAI says studies have not shown that cats can be hypoallergenic.⁴ The AAAAI says there are no “hypoallergenic” breeds of dogs or cats.²

US agencies and allergy societies describe these ways to cut exposure:

• Keep the cat out of the bedroom and limit it to a few rooms. Keeping it in one room will not keep the allergen there.⁴
• Keep pets off upholstered furniture, and use an air cleaner with a HEPA filter.⁶
• Vacuum carpets often, or replace them with hardwood, tile or linoleum.²
• Wash your hands with soap and water after touching a pet.⁴

Bathing a cat helps only for a short time: Fel d 1 on the skin and fur returns to its usual level within about two days.¹ The EPA says the most effective way to control animal allergens is to not have the animal in the home.⁶