Allergic Emergencies (Anaphylaxis) Bee-stings and peanuts may cause fatal allergic shock   Anaphylaxis is a very serious manifestation of the allergic response that may become life-threatening if not treated immediately and properly. Anaphylaxis literally means without protection. It is an IgE-mediated reaction that results when mast cells suddenly release chemical mediators that overwhelm the body.   The onset of anaphylaxis is usually sudden. Symptoms develop within minutes after exposure to specific triggering allergens; and may result in death within less than two hours for severe cases. Symptoms of anaphylaxis:   The first evidence of anaphylaxis may be swelling and redness of the skin, often accompanied by hives;   The patient may experience a feeling of great anxiety, vomiting, abdominal cramps, and diarrhea;   Life-threatening breathing difficulties may develop due to swelling of the larynx or severe bronchospasm;   A drastic drop in blood pressure may result in potentially fatal shock;   In many severe cases, irregular heart beats develop.   Prevention remains the best treatment for anaphylaxis. However, anaphylaxis may occur without warning. In all cases, rapid treatment is essential.   Causes of Anaphylaxis (Emergency Allergic Reactions) Anaphylactic reactions may be induced by drugs, vaccines, diagnostic and therapeutic allergens, insect stings, foods, very cold temperature and blood transfusion etc. (Remark: Anaphylactoid reactions have symptoms the same as those of anaphylaxis, but antibodies do not play a role in such response. Anaphylactoid reactions may be induced by injected dyes and aspirin.) 1.  Drug-induced anaphylactic reactions   Penicillin-induced anaphylaxis is an immediate allergic reaction that begins 2 to 30 minutes after the patient takes the first dose of this antibiotic. About 2% of patients who receives penicillin have some sort of allergic reactions to it. About 1 in 2,500 patients suffers anaphylaxis; and about 1 in 100,000 dies.   2.  Reactions to vaccines   Adverse reactions to vaccines may range from mild to fatal, and may be immunologic or non-immunologic. Vaccines that may lead to anaphylactic reactions include: tetanus and diphtheria; whooping cough, typhoid, paratyphoid, cholera, plague and tuberculosis; viral vaccines; rubella, mumps, rabies and yellow fever.   3.  Reactions to diagnostic and therapeutic allergens   A variety of diagnostic and therapeutic allergens can produce serious IgE-mediated allergic reactions. The severity and speed which these develop depend on the nature of the agent, its concentration, how rapidly it is absorbed, and the sensitivity of the patient. In rare occasions, an allergen used in diagnosing allergies can cause anaphylaxis under certain circumstances in an extremely allergic person.   4.  Anaphylactic Reactions to Insect Stings   Insect stings can induce anaphylactic reactions in an estimated 0.4% of the population. It is often difficult to identify the insect responsible for an allergic reaction. Bees leave their stingers, but other insects do not. The most common insect causing allergic reactions is the yellow jacket, followed by the bee, wasp, and hornet. Certain ants inject venom that can cause potentially fatal allergic response. For example, the fire ants cause painful stings that may lead to severe allergic reactions.   5.  Anaphylactic reactions to food   Some people are highly allergic to foods such as nuts, fish, eggs, and seeds. Just a minimal exposure to these foods can provoke severe symptoms. Less common are severe reactions to milk, chocolate, grains (barley, rice, wheat), various fruits including tomatoes, and such vegetables as corn, spinach, potatoes, and soybeans. Some chocolates contain almond flavoring which can trigger an allergic reaction. Some candies like jelly beans or other coated confections may use dyes or spices that can cause an allergic response. As licorice is a legume, it can cause problems for children allergic to peanuts.   Other foods that may be lead to allergic reactions include chestnuts, spices, wine, smoked salmon, cranberries, squash, egg-whites, ice-cream, cinnamon or glazed apples, insecticide residue on fruits etc. Once a food allergy is diagnosed, it is important for the patient to avoid the food.   6.  Anaphylactoid reaction to injected dyes   Life-threatening allergic reactions may happen due to the use of dyes injected into the body of patients for certain x-ray studies (e.g. for kidney studies). These reactions present a problem because the use of these dyes is a vital part of many sophisticated x-ray studies. In a number of serious illnesses, there is no substitute for the diagnostic procedure and the dye.   7.  Cold-induced urticaria (hives)   Hives may develop in response to cold temperature. For severe cases, cold-induced urticaria can result in a drastic drop in blood pressure, shock and even death. The exact causes of the disorder remain unknown.   8.  Reactions to transfusion of blood or blood products   An anaphylactic reaction may follow a blood transfusion to people who are born without IgA antibodies, roughly 1 in every 700 persons. When these people are given transfused blood, his body makes IgE antibodies against the IgA antibodies he receives in the transfusion. If the patient receives transfusion again, these IgE antibodies rapidly attack the IgA antibodies in the serum of the new blood, resulting in life-threatening anaphylaxis.   Patients who are transfused with whole blood or red blood cells that are incompatible with their own may develop allergic reactions, ranging from mild to severe. The allergic reaction develops rapidly, either while receiving the blood or shortly thereafter. Symptoms may include a feeling of warmth in the arm or along the vein being transfused, rapid heart beat, facial flushing, headache, pain in the lower back, chest pains, chills followed by fever, hives, vomiting, and diarrhea. In severe cases, a drastic drop in blood pressure may occur, as well as widespread blood clots, bleeding and kidney failure.   9.  Reactions to aspirin   Aspirin may induce severe, even life-threatening reactions that closely resemble anaphylaxis. Aspirin can also result in hives and swelling of the upper airway, which may require emergency action to restore breathing. The onset of severe symptoms may come within 15 minutes after taking aspirin, or it may not occur for hours. In such cases, it is often difficult to relate the use of aspirin to the reaction.   Aspirin is extensively used, and it ranks with penicillin as one of the most frequent causes of adverse drug reactions. The exact mechanism of the aspirin reaction remains uncertain. So far, no antibodies to aspirin have been found. Patients with bronchial asthma, especially those who also have nasal polyps, appear to have a high reaction rate to aspirin. Estimates run as high as 7%, and the risk of suffering an aspirin reaction increases with age in asthma patients.