Severe allergic reaction may need more epinephrine

NEW YORK (Reuters Health) - Nearly one in five food-induced anaphylactic reactions that occur in children with multiple food allergies will require two or more doses of epinephrine, rather than a single dose that is usually administered, new research suggests.

Anaphylaxis is a severe allergic reaction that develops quickly, within seconds or minutes of exposure, causing a life-threatening response of the immune system involving the whole body. The immune system releases histamine and other substances that cause tightening of the airways and shock. Common causes of anaphylaxis are foods, drugs or insect bites.

The treatment, which should be given as soon as possible, is an epinephrine injection. The drug causes rapid heart beat, more forceful heart contractions, and opens the airways in the lungs, along with other effects. Epinephrine is also secreted in the body by the adrenal glands, and is part of the "fight-or-flight" reaction.

As reported in an upcoming issue of the Journal of Allergy and Clinical Immunology, Dr. Kirsi M. Jarvinen, from Mount Sinai School of Medicine in New York, and colleagues evaluated epinephrine use in children with food allergies by surveying the families of 413 patients.

Overall, 78 children, who were an average of 4.5 years old, were given epinephrine to treat a total of 95 reactions, the report indicates. Over 75 percent of these reactions involved peanut, tree nut, or cow's milk allergies.

Twelve (13 percent) of the reactions required two doses of epinephrine and an additional 6 (6 percent) required three doses, the researchers found.

Children who also had asthma were more likely to need multiple doses of epinephrine, whereas the amount of food eaten and delay of epinephrine treatment seemed to have no effect.

"Our survey performed in a highly selected patient population indicates that a significant number of respondents received a second dose of epinephrine," the authors conclude. "Prospective studies are needed to identify risk factors for severe anaphylaxis and to establish rational guidelines for prescribing multiple epinephrine autoinjectors for children with food allergy."

SOURCE: Journal of Allergy Clinical Immunology 2008.