THE basketball game was getting intense when 17-year-old Ralph started to feel itchy all over his body. One of his friends, Michael, asked if something was wrong. “I’m having difficulty breathing,” Ralph told him.
Having completed an emergency first aid course, Michael suspected his friend was having a severe allergic reaction and asked I he’d been stung by a bee. Ralph answered negatively.
Michael asked what he had eaten for supper. Ralph said his mother had served fried prawns. When Ralph started to lose consciousness, Michael immediately asked someone to drive his friend to a nearby medical center, where a doctor quickly stabilized him.
Ralph recovered fully, and now avoids crustaceans and carries an EpiPen – an auto injector of epinephrine – in case of another allergic reaction.
What Ralph experienced was anaphylaxis. Worldwide, 0.05 to 2 percent of people are estimated to have anaphylaxis at some point in their life and rates appear to be increasing. The term comes from two Greek words: ana (against) and phylaxis (protection). Dr. Charles Richet coined the word in 1902 and eleven years later, he won the Nobel Prize in Medicine and Physiology for his worn on anaphylaxis.
“Anaphylaxis is an acute life-threatening episode that requires immediate medical attention,” says Dr. Manmohan Yadav, a consultant allergist at Pantai Medical Center in Kuala Lumpur and author of Cause and Prevention of Allergy and Asthma.
Anaphylaxis can occur in response to almost any foreign substance. Common triggers include venom from insect bites or stings (from bees and wasps), foods, and medication. Foods are the most common trigger in children and young adults while medications and insect bites and stings are more common in older adults.
Common triggering foods include peanuts, wheat, shellfish, fish, milk, and eggs. The most common medication that may trigger anaphylaxis are antibiotics (such as penicillin), aspirin, and non-steroidal anti-inflammatory drugs (NSAIDs).
Less common causes of anaphylaxis include: physical factors, biological agents such as semen, latex, hormonal changes, food additives such as monosodium glutamate and food colors, and topical medications. Physical factors such as exercise (known as exercise-induced anaphylaxis) or temperature (either hot or cold) may also act as triggers through their direct effects on mast cells.
People with atopic diseases such as asthma, eczema, or allergic rhinitis are at high risk of anaphylaxis from food, latex, and radiocontrast but not injectable medications or stings. One study in children found that 60 percent had a history of previous atopic diseases, and of those who die from anaphylaxis more than 90 percent have asthma.
“Like other allergic reactions, an anaphylactic reaction does not usually occur after the first exposure to an allergen but may occur after a subsequent exposure,” explains The Merck Manual of Medical Information. “However, many people do not recall a first exposure.”
“It’s easier to identify anaphylactic shock if there is a known allergen,” writes Dr. John Krohmer in First Aid Manual. “For instance, those with allergies to bee stings will usually know they’ve been stung. Sometimes, however, there is no known allergen and the victim is simply developing symptoms of anaphylaxis.”
According to the Merck manual, anaphylactic reactions begin within one to 15 minutes of exposure to the allergen. “Rarely, reactions begin after one hour,” the manual points out. “The heart beats quickly. The person may feel uneasy and become agitated. Blood pressure may fall, causing fainting.”
Other symptoms include tingling (pins-and-needles) sensations, throbbing in the ears, coughing, sneezing, hives, and swelling. Breathing may become difficult and wheezing may occur because the windpipe (upper airway) constricts or becomes swollen.
“An anaphylactic reaction may progress so rapidly that it leads to collapse, cessation of breathing, seizures, and loss of consciousness within one to two hours,” the Merck manual states. “The reaction may be fatal unless emergency treatment is given immediately.”
A medical emergency, anaphylaxis requires resuscitation measures such as airway management, supplemental oxygen, large volumes of intravenous fluids, and close monitoring. Administration of epinephrine is the treatment of choice with antihistamines and steroids 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.
People prone to anaphylaxis are advised to have an “allergy action plan,” and parents are advised to inform schools of their children’s allergies and what to do in case of an anaphylactic emergency. The action plan usually includes use of epinephrine auto-injectors, the recommendation to wear a medical alert bracelet, and counseling on avoidance of triggers.
What would you do if you were in the shoes of Michael? First, call any of the emergency medical services in your area. Then, ask the victim if he has an injector kit he can use. If the victim is unconscious, you’re certain it’s an allergic reaction, and if you are trained to use the EpiPen, do so.
While waiting for the emergency response team, monitor the victim. If needed, proceed with cardiopulmonary resuscitation (CPR). CPR, the cornerstone of emergency medicine, is putting oxygen into the victim’s lungs by performing rescue breathing, and circulate it through the body by doing chest compressions.
“By recognizing both the early symptoms of anaphylactic shock, and the later, more dramatic symptoms such as respiratory distress and unconsciousness, you may be able to summon emergency help for yourself, someone you love or even a perfect stranger,” the e-How Health contends.