Epidemiology
The number of people who get anaphylaxis is 4–100 per 100,000 persons per year, with a lifetime risk of 0.05–2%. About 30% of people get more than one attack. Exercise-induced anaphylaxis affects about 1 in 2000 young people.Rates appear to be increasing: the numbers in the 1980s were approximately 20 per 100,000 per year, while in the 1990s it was 50 per 100,000 per year. The increase appears to be primarily for food-induced anaphylaxis. The risk is greatest in young people and females.Anaphylaxis leads to as many as 500–1,000 deaths per year (2.7 per million) in the United States, 20 deaths per year in the United Kingdom (0.33 per million), and 15 deaths per year in Australia (0.64 per million). Another estimate from the United States puts the death rate at 0.7 per million. Mortality rates have decreased between the 1970s and 2000s. In Australia, death from food-induced anaphylaxis occur primarily in women while deaths due to insect bites primarily occur in males. Death from anaphylaxis is most commonly triggered by medications. History
The conditions of anaphylaxis has been known since ancient times. French physician François Magendie had described how rabbits were killed by repeated injections of egg albumin in 1839. However, the phenomenon was discovered by two French physiologists Charles Richet and Paul Portier. In 1901, Albert I, Prince of Monaco requested Richet and Portier join him on a scientific expedition around the French coast of the Atlantic Ocean, specifically to study on the toxin produced by cnidarians (like jellyfish and sea anemones).
Laboratory findings could detect increased levels of serum tryptase, increase in total and specific IgE serum levels. Prevention
Avoidance of the trigger of anaphylaxis is recommended. In cases where this may not be possible, desensitization may be an option. Immunotherapy with Hymenoptera venoms is effective at desensitizing 80–90% of adults and 98% of children against allergies to bees, wasps, hornets, yellowjackets, and fire ants. Oral immunotherapy may be effective at desensitizing some people to certain food including milk, eggs, nuts and peanuts; however, adverse effects are common. For example, many people develop an itchy throat, cough, or lip swelling during immunotherapy. Desensitization is also possible for many medications, however it is advised that most people simply avoid the agent in question. In those who react to latex it may be important to avoid cross-reactive foods such as avocados, bananas, and potatoes among others. Management
Anaphylaxis is a medical emergency that may require resuscitation measures such as airway management, supplemental oxygen, large volumes of intravenous fluids, and close monitoring. Passive leg raise may also be helpful in the emergency management.Administration of epinephrine is the treatment of choice with antihistamines and steroids (for example, dexamethasone) often used as adjuncts. A period of in-hospital observation for between 2 and 24 hours is recommended for people once they have returned to normal due to concerns of biphasic anaphylaxis. Epinephrine
Epinephrine (adrenaline) (1 in 1,000) is the primary treatment for anaphylaxis with no absolute contraindication to its use.