If you’re like most allergic people, chances are good that you’ll never have a life-threatening reaction. Even then, there’s only one chance in a million that the reaction will be fatal – and those odds are less than that if you know how to handle it.
As with choking or heart failure, a severe allergic reaction calls for immediate first aid. The first ten or fifteen minutes are the most critical. (The very most you can hope for is an hour – then it might be too late.) But that ‘grace period’ still doesn’t give you much time to locate and reach a doctor. So it’s imperative that you learn to recognize an allergic emergency and know exactly what to do about it.
As the term implies, an allergic emergency is a reaction that can be fatal. The most common life-threatening reaction is anaphylaxis – an explosive body wide response to an allergic encounter. The individual first becomes weak, pale, anxious, dizzy, has hoarseness or difficult breathing – then usually collapses. That may be followed by any of various symptoms, involving four major organ systems:
– gastrointestinal tract: nausea, vomiting, stomach cramps, bloating and diarrhoea;
– skin: intense flushing, itching, hives and swelling (especially swelling at the site of an insect sting);
– heart and blood vessels: rapid heartbeat and low blood pressure (this is itself also known as anaphylactic shock); and
– respiratory tract: sudden runny nose, swollen vocal cords, uncontrollable coughing, wheezing, bronchospasm and constricted airways (caused by internal swelling).
The basis of all anaphylactic symptoms is an overwhelming surge of histamine and other allergy-provoking substances (for example, newly recognized leucotrienes) from mast cells and basophils, the allergen-sensitive tissues.
Of those symptoms, however, the biggest threat to life is constricted airways, which can cause death within minutes if not opened. The second is low blood pressure, or shock.
Penicillin is the most common cause of anaphylaxis and accounts for about three out of four fatal reactions. It’s followed byin order of incidence – venomous insect stings, radiographic dye (a diagnostic medium), aspirin and related drugs, and foods such as eggs, nuts or seafood.
Less common than anaphylaxis but equally threatening is laryngeal oedema (swelling of the windpipe or throat). It may occur alone or as part of anaphylaxis. A severe, uncontrollable form of asthma called status asthmaticus is also considered an emergency.
The symptoms of a serious asthma attack are:
– an attack that fails to improve or is increasing in severity after several hours, or that does not respond to routine drugs;
– wheezing that is first loud and then stops, accompanied by extremely labored and difficult breathing;
– fatigue and weakness;
– irregular heartbeat, or a pulse higher than 140 beats per minute (or higher than 160 in children under age six); and
– obvious bulging of the neck muscles, expanded chest cage, sweating and noticeable deepening of the notch over the breastbone.