Allergen: What a person with allergies is triggered by during an allergic reaction.

Allergy: An abnormal response to a substance that occurs when the body’s immune system cannot tolerate it.

Anaphylaxis: A severe allergic response that may be life-threatening. Symtoms include low blood pressure, swelling, difficulty breathing and hives.

Antihistamine: Medication that balances the body’s histamine levels and prevents/treats allergy symptoms like congestion, sneezing and runny nose.

Decongestant: A medication, often an antihistamine or an anti-inflammatory, that relieves swollen nasal tissues and symptoms of mucus congestion.

Dermatitis: Skin inflammation, usually an allergic reaction caused by direct contact with an allergen.

Dust Mites: Microscopic insects that live off the dead skin cells found in dust. These are a common household allergen.

Hay Fever: Allergies related to pollen, grass and other plants. People with hay fever usually exhibit symptoms in the spring and summer.

Histamine: Naturally occurring in the body, this substance is released by the immune system when it is exposed to an allergen.

Hives: Itchy, swollen red bumps or patches on the skin. Can occur anywhere on the body and are caused by an allergic reaction.

Immunotherapy: An allergy treatment that gradually increases your tolerance to allergens through long-term exposure. Usually administered as allergy shots or drops.

Nasal Endoscopy: A test wherein a doctor examines your nasal cavity to identify polyps or other issues.

Nasal Sprays: Medication that prevents or treats nasal symptoms. Usually a decongestant, antihistamine or saline spray.

Pollen: A common allergen related to hay fever. It is the fine, powdery substance released by plants in the springtime.

Skin Test: The most common allergy test wherein a doctor pricks the skin on the arms or back and introduces extracts of common allergens to illicit an allergic response.

Sinusitis: Inflammation of the sinuses usually caused by a virus or by allergies. Usually treated by antibiotics and/or decongestants.