An allergy is an overly sensitive (hypersensitive) disorder of immune system. If you are allergic, your immune system responds to your triggers in an abnormal way.
These triggers are called allergen or antigen. Antigens include pollen, dust mites, mold spores, pet dander, food, insect stings, and medicines.
Allergens enter your body by four different routes:
- Contact allergens enter your skin by touch. Example: poison ivy, latex gloves, jewelry.
- Ingestion. Example: food, drugs.
- Injection. Example: medications, bee sting.
- Inhalation. Example: pollens, dust mite, molds, animal dander.