Cat dander is made up of microscopic flecks of skin that are shed by cats. It is responsible for the majority of human allergies to cats. Dander is dead skin cells that are regularly sloughed off and replaced by new skin cells. All cats produce dander, but not all people are allergic to it. Cat dander can trigger an allergic reaction in some people, causing symptoms such as itchy, watery eyes, nasal congestion, coughing, shortness of breath, skin rash, or hives.

Cat dander is not the same as cat fur, and it can remain suspended in the air for a long period of time and easily stick to furniture, bedding, fabrics, and many other household items. Proteins found in cat saliva, urine, and feces can also cause allergic reactions. To limit pet dander and reduce allergies, it is recommended to bathe your cat weekly with products labeled specifically for your pet. Additionally, there are medications, house cleaning methods, and immunotherapy that can help reduce discomfort or severity of reaction upon exposure to cat dander.