Short answer
Cat hair itself is not generally thought to be the main cause of asthma. The usual trigger is a set of proteins from cats, called allergens, which can cling to hair and float in the air. For a person who is sensitive to them, breathing these in can set off symptoms, including in people who already have asthma.
This page is general information, not medical advice for people. If you have breathing symptoms, talk to a doctor.
What actually triggers symptoms in people
The best-known cat allergen is a protein called Fel d 1. It is found in cat saliva and skin glands, and other cat proteins can also play a role. Cats spread these by grooming, shedding (see cat shedding season) and shedding skin flakes (dander). The particles are very light and can settle on furniture, carpets, clothing and bedding, and may stay in a home for a long time even after a cat has gone.
Hair is mostly a carrier. A cat with short or little hair can still produce allergens.
Allergy vs asthma
An allergy is an immune reaction. It may cause sneezing, itchy or watery eyes, a runny nose or a skin rash such as hives. Asthma is a condition of the airways, with coughing, wheezing, chest tightness or breathlessness. Allergens can trigger asthma in some people, so the two can happen together. If you are wondering whether an allergy can appear later in life, see how people develop a cat allergy. A doctor can help work out which applies.
Does keeping cats cause asthma?
Research on whether living with a cat causes asthma is mixed and the picture is complicated. What is clearer is that exposure can worsen symptoms in people who are already sensitized. If you or a family member has asthma, discuss pet ownership with your doctor before bringing a cat home.
Reducing allergen exposure at home
Steps people often try include:
- Keeping the cat out of the bedroom
- Washing bedding frequently
- Vacuuming often, ideally with a HEPA filter
- Using air purifiers with HEPA filters
- Choosing hard floors over thick carpets where possible
- Washing hands after handling the cat
- Having a non-allergic family member clean the litter box
These steps may help some people, but results vary and they may not remove symptoms entirely.
Hypoallergenic cats: what to know
Some breeds are marketed as hypoallergenic. Evidence that any cat is completely allergen-free is limited, and individual cats within a breed differ. Spending time with a particular cat before adopting can tell you more than a breed label.
What about asthma in cats themselves?
Cats can develop asthma too. Their airways may react to dust, smoke, scented products and some litters. This is a separate matter from human allergy. If your cat coughs or wheezes, see our guide to telling a cat asthma attack from a hairball. Feline asthma generally needs ongoing management rather than a one-time cure, and your vet can explain what to expect.
Can a cat allergy cause hives?
Allergic reactions to animals can show up on the skin, including as itchy raised welts in some people. See a doctor if this happens, and seek urgent care for swelling of the face or throat or difficulty breathing.
When to talk to a doctor
See a doctor if you have repeated sneezing, wheezing, coughing or chest tightness around cats. Get urgent help for severe breathlessness. An allergy specialist can test for specific allergies and suggest treatment options.