Cat allergen is one of the most common indoor allergens, and often causes symptoms like sneezing, runny nose, and itchy eyes – known as allergic rhinitis. This can lead to other health issues such as eye irritation, asthma, sinus infections, and sleep problems. People with allergic rhinitis often report that it affects their quality of life, work, and school performance. While there are many treatments available, studies show that up to 60% still struggle with symptoms. Understanding how cat allergens impact the immune system will help us to find better ways to treat cat and other allergies.