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Allergy & Asthma Advocate: Spring 2006
Causes of anaphylaxis and epinephrine optionsBy Andy Nish, MD, FAAAAI Anaphylaxis is a severe, generalized allergic reaction. The word anaphylaxis literally means “to remove from protection.” By its nature, anaphylaxis is potentially life-threatening and involves more than one of the body’s systems. Why should we worry about anaphylaxis? Does it occur commonly? Odds are that you or someone you know has been affected. Exact numbers are hard to come by, but it is estimated that 1% to 17% of the United States population may experience anaphylaxis each year, resulting in 1500 deaths per year. Symptoms of anaphylaxis commonly include those in the skin such as itch, hives or urticaria, swelling or angioedema and flushing. Respiratory symptoms might include wheeze, cough, shortness of breath and chest tightness, throat tightness, swelling in the throat, or change in voice. At times eyes itch and the nose will become congested. Rapid heart rate may occur and low blood pressure may cause dizziness. Nausea, vomiting and abdominal cramping indicate involvement of the gastrointestinal tract. Symptoms may start mildly and rapidly progress to severe. Since anaphylaxis is a life-threatening situation, it is crucial to seek emergency medical care immediately. In addition, some episodes of anaphylaxis will improve initially then worsen again. This is called biphasic anaphylaxis and is another reason that expert medical care is necessary. There are a number of potential causes of anaphylaxis. Allergists are specially trained in the evaluation and treatment of anaphylaxis and similar reactions.
Medications also frequently cause serious allergic reactions. Those in the penicillin class and their relatives, the cephalosporins, are some of the most common. It is estimated that up to 10% of people are allergic to penicillin. Not all exposures, even in those who are allergic, will lead to a reaction with the severity of anaphylaxis. Other medications liable to cause anaphylaxis include sulfa antibiotics, chemotherapeutic agents for cancer, aspirin and insulin. It should be noted that anaphylaxis could occur with almost any medication in a given person, even if very few people in general are allergic to it.
Various causes of anaphylaxis or anaphylaxis-like reactions include radiocontrast media, or dye used during radiologic procedures. Latex allergy is particularly prevalent among health care workers and people who have had multiple surgeries. Anaphylaxis has been reported to dyes and other food additives, v a c c i n e s , allergy shots and blood p r o d u c t s . Idiopathic anaphylaxis is defined by typically recurrent episodes for which no cause is i d e n t i f i e d after extensive evaluation. The treatment of anaphylaxis starts with avoidance of the offending agent, if known. Evaluation of anaphylaxis by an allergist is crucial. There is no definitive treatment for foods, medicines, etc other than avoidance. As noted previously, immunotherapy is available and extremely effective for stinging insect allergy.
Both come in a size for children up to about 70 pounds and a size for adults. Both have a dose which is automatically injected into the thigh when activated. Proper instruction at your allergist’s office in use of these devices is crucial. Anyone who might potentially need to administer the injection should feel comfortable with the steps necessary to use it. So we see that knowledge is the key to dealing with anaphylaxis. Knowing the symptoms, cause(s), avoidance measures and treatment for anaphylaxis is potentially life-saving. Your allergist is your best resource in dealing with this serious condition. |
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Foods are one of the most common causes of anaphylaxis. It is estimated that up to 8% of children and 1-2% of adults are allergic to foods. The most common food allergies for children include milk, egg, peanut and soy, while adults tend to be allergic to fish, shellfish (like shrimp), tree nuts such as cashews and wheat. Symptoms from food allergies tend to occur within minutes of food ingestion; rarely anaphylaxis has been reported several hours after eating. Food-associated exercise-induced anaphylaxis is caused by a combination of eating a particular food, often celery or wheat, plus exercise within an hour or two after eating.
It is estimated that 3% of the United States population is allergic to insect stings. These reactions commonly occur during such activities as mowing the lawn, gardening, playing outdoor sports and eating outdoors. Not only flying insects such as honeybees and wasps but also crawling insects such as fire ants, particularly in the southern United States, can cause anaphylaxis. There are avoidance measures that should be observed, and anaphylaxis to stinging insects is one of the few areas for which there is definitive treatment in the form of immunotherapy, or desensitization.
Adrenaline, or epinephrine, is the primary treatment for anaphylaxis and comes in prescription forms which can be carried by the patient and should always be immediately available. The two devices currently on the market are the Epi-Pen™ and the Twinject™. The Twinject™ has the added advantage of an extra dose of epinephrine.