Anaphylaxis or anaphylactic shock occurs as a result of exposure to an allergen that the body’s immune system is highly sensitive to. Only a very small amount of a particular allergen can cause a severe hypersensitivity allergic response. It can occur after eating, inhaling, when the skin comes into contact with something or after an injection.  In cases of anaphylactic shock, the body releases a massive amount of immunological substances including histamines which leads to rapid loss in blood pressure, swelling of the nasal and throat passages and difficulty in getting air into the lungs (respiratory difficulties). Death can follow in mere minutes if immediate medical attention is not received. This is usually in the form of a shot of adrenaline (a hormone in the body that elevates the heart rate and increases the circumference of blood vessels and air passages). The most common triggers of anaphylaxis are peanuts, shellfish and insect stings.