Anaphylaxis
Many people experience chronic allergy symptoms that often interfere with their quality of life. The allergy symptoms in most people are usually present in one or two organs, for example nose and skin or nose, sinus and lungs. However, a small number of highly allergic individuals are susceptible to a most serious form of allergic reaction known as anaphylaxis that occurs rapidly and involves many organs of the body, such as the skin, respiratory tract, gastrointestinal tract, and cardiovascular system. Thus, anaphylaxis is an acute life-threatening episode that requires immediate medical attention. Symptoms normally appear rapidly, usually within minutes, after exposure to an allergen. In rare cases the anaphylactic reaction may be delayed for 12 to 24 hours. Generally, most anaphylactic events occur at home in infants, children and adults. Many types of agents, for example drugs, foods, and insect venoms, can cause anaphylaxis. The anaphylaxis may be IgE mediated or non-IgE mediated. The anaphylaxis triggered by various agents can cause different types of clinical manifestations but the most frequent symptoms involve the respiratory system (78%) and the skin (90%). The anaphylactic reactions involving the respiratory system are often life-threatening and immediate emergency medical treatment is required.

Early symptoms of anaphylaxis may include itchiness of palms or soles or roots of hair and followed by swelling of the face, sensation of faintness, feeling of generalized warmth, tingling sensation all over, or metallic taste in the mouth, discomfort in throat or chest, and breathing difficulty. Typical symptoms of anaphylaxis include the following: