Zocdoc Answers

Medical questions & health advice by licensed doctors

"Can you suddenly develop an allergy to cats?"


Never had trouble with cats before, but just got a new housemate that has one. I'm sneezing a lot and my eyes are itchy. Could I be allergic to cats? Why would this be happening now, when I'm 28?


An allergic reaction occurs when your immune system mistakenly believes substances that are harmless to most people to be harmful to your body and responds by producing immunoglobin E (IgE) antibodies to destroy what your body has perceived as foreign invaders (allergens). These IgE antibodies trigger the release of histamines, leukotrienes, and other chemicals to cause allergy symptoms. You do develop allergies from repeated exposure to the allergen.

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Therefore, anyone can develop or grow out of allergy symptoms at any time. Your age also has something to do with developing allergies. Since repeated exposure to certain allergens can trigger an allergic reaction, it is possible to develop allergies when you're older, as you've had more time to be in contact with the allergens. It is possible that you suddenly develop an allergy to cats. You may be allergic to certain chemicals in pet dander to trigger histamines in your bodies. That said, you should take notice if you are allergic to other cats as well. If you notice that only your roommate's cat gives you the allergic symptoms, perhaps you are allergic to something else. Perhaps you are allergic to the ragweed that is bloomed in the area and the cat is carrying the spores from that ragweed into the house on its fur. The best way to truly know is to see an allergy specialist or primary care doctor to have it checked out so you can be treated accordingly.

Zocdoc Answers is for general informational purposes only and is not a substitute for professional medical advice. If you think you may have a medical emergency, call your doctor (in the United States) 911 immediately. Always seek the advice of your doctor before starting or changing treatment. Medical professionals who provide responses to health-related questions are intended third party beneficiaries with certain rights under Zocdoc’s Terms of Service.