Although the majority of children outgrow allergies to bee, wasp and other insect stings, almost one in five who had allergic reactions when stung as children - especially those who had serious allergic reactions - are likely to have reactions later in life, according to a study by Johns Hopkins scientists.
"Contrary to popular wisdom, a great number of children do not outgrow allergic reactions to insect stings," says David Golden, M.D., associate professor of medicine at Johns Hopkins and lead author of a report on the study appearing in the Aug. 12, 2004 issue of the New England Journal of Medicine. "The good news is that for children with moderate to severe reactions, allergy shots will lower the risk of serious reactions to stings even 10 to 20 years after treatment is stopped."
Allergy shots, or venom immunotherapy, give purified bee or other insect venom in small doses that build up over time and are recommended for children who have moderate or severe reactions, including dizziness, breathing difficulty and lowered blood pressure. There is little need for the therapy in children with milder reactions, such as minor swelling and hives, said Golden.
Between 1978 and 1985, the researchers diagnosed allergic reaction to insect stings in 1,033 children, of whom 356 subsequently received venom immunotherapy. To determine how many children outgrow their allergies to insect stings, the researchers collected follow-up information on more than 500 of these children, of whom 40 percent had received stings in the six to 32 years after their first reaction.
The researchers conducted a survey of these patients by telephone and by mail between 1997 and 2000. Patients were asked to describe their reactions and were provided with a standard list of questions about symptoms, the length of the reaction, and how the reaction was treated. Mild reactions affected only the skin and involved hives and minor swelling. Moderate reactions included skin reactions, but also throat and chest discomfort, difficulty breathing, dizziness and low blood pressure. Severe reactions included skin reactions, but also marked difficulty breathing, severe dizziness and marked low blood pressure or unconsciousness.
The researchers found that moderate and severe reactions occurred less frequently in adults who had received venom immunotherapy as children (3 percent) than in those who had not (17 percent). Patients with a history of moderate or severe reactions had a higher rate of reaction if they had not been treated (32 percent) than if they had received venom immunotherapy (5 percent). The average duration of venom immunotherapy was three and a half years. This report describes the longest-lasting effects of allergen immunotherapy yet observed, said Golden.
Other authors of the report are Lawrence Lichtenstein, M.D., Ph.D., Robert Hamilton, Ph.D., Philip Norman, M.D., and Anne Kagey-Sobotka, Ph.D., all from Johns Hopkins. The study was supported by the National Institutes of Health.