Allergens, also called antigens, are substances that can trigger an
allergic reaction. Having allergies means that the body reacts to allergens as
a harmful foreign substance.
Allergens may be:
- Inhaled in the form of pollens, mold,
chemicals, material from the stools of cockroaches and house dust mites, or
animal dander and saliva. Animal dander is dead skin cells from an animal, such
as a cat or dog. Animal hair or fur is not an allergen.
- Eaten or
taken by mouth, including foods, food supplements, home remedies, or
- Touched, such as cosmetics, plants, soaps or
detergents, chemicals, metals, or latex (causing skin or contact
- Applied to the skin, such as artificial nails, hair
extensions, or henna tattoos.
- Injected under the skin, such as
medicines or venom from the bites or stings of bees, yellow jackets, hornets,
or other insects.
Allergy symptoms may be controlled by avoiding exposure to
allergens. Some people need medicines or allergy shots (immunotherapy) to
control their body's reactions to the allergens.