Anaphylaxis is a sudden severe body-wide allergic reaction to an allergen exposure that occurs rapidly and causes a potentially fatal condition known as anaphylactic shock. When a body goes into anaphylactic shock, the blood pressure suddenly drops preventing the heart from receiving oxygen and the airways are constricted, which makes breathing extremely difficult.

There are varying triggers of anaphylaxis, including allergies to medications, food (such as peanuts, tree nuts, shellfish, eggs, and milk), insect stings and latex products. Although allergic reactions to environmental triggers such as pollens and animals can be very unpleasant and bothersome, these do not typically trigger anaphylaxis.

Anaphylaxis is a true medical emergency. It can be life-threatening if not treated quickly and appropriately. In general, treatment of anaphylaxis includes the immediate use of epinephrine auto-injector (EpiPen), a form of adrenalin and observation by a highly trained physician.