Skip Navigation

Definition: Allergen

Definition: Allergen


An allergen is a medical word for anything that causes an allergic reaction. Allergens can be many different things, including grass, dust mites, or animal dander - the stuff that flakes off dogs' and cats' skin.

Note: All information on TeensHealth® is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.

© 1995- The Nemours Foundation. All rights reserved.

Images provided by The Nemours Foundation, iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and