**If you are allergic, an allergen can trigger sneezing, a runny nose, itching, hives, swelling, or wheezing.**
An allergen is a substance that triggers an allergic reaction, such as pollen, pet dander, or certain foods. Your symptoms depend on the trigger and whether you breathe it in, swallow it, or touch it. Some reactions also cause stomach cramps, vomiting, or diarrhea. Avoid known triggers and record when symptoms occur to help your clinician decide whether allergy testing is needed.
How to manage your allergies
Common questions
What are the symptoms of Allergen?
An allergen is an allergy trigger, not an illness. If you are allergic to it, you may develop sneezing, a runny or stuffy nose, itching, hives, swelling, coughing, or wheezing. Some reactions cause vomiting, diarrhea, or stomach cramps. Symptoms alone cannot identify the trigger; see a clinician for recurring or unexplained reactions. Trouble breathing, throat or tongue swelling, or fainting can signal anaphylaxis. Use your prescribed epinephrine immediately if available and call 911. Antihistamines do not replace epinephrine for anaphylaxis.