Environmental allergies are generally known as allergic rhinitis. This is an allergic reaction that occurs in the nose when allergens in the air trigger the release of histamine. Histamine makes it difficult to breathe, causing inflammation, nasal congestion, swelling of the nasal membranes, blockage and reduction of normal sinus drainage.
Anaphylaxis is a medical emergency that requires immediate attention. Learn what to do if you develop anaphylaxis and how you can help prevent this potentially life-threatening allergic reaction.