Insect venom shots work for severe "local" sting reactions, too

The same bee and other insect venom shots that doctors use to prevent deadly systemic reactions to insect stings can also tone down large local allergic reactions that, while not dangerous, can be painful and inconvenient, a Johns Hopkins study shows. Results of the study are published in the June 2009 Journal of Allergy and Clinical Immunology.

Venom therapy, in which small periodic injections of venom from bees, wasps and other stinging insects build up immunity among those susceptible to potentially lethal anaphylactic shock from stings, has had widespread use since it was developed in the 1970s at Johns Hopkins. However, people who suffer frequent large localized reactions because of jobs or hobbies such as landscaping, gardening and golfing, are generally denied this treatment. Though these localized reactions aren't life-threatening, they can be extremely painful and cause massive swelling that lasts for days.

"We just didn't know if venom therapy would work or cause problems for these patients," says David Golden, M.D., an associate professor of medicine at the Johns Hopkins University School of Medicine.

To find out, he and his colleagues recruited 41 volunteers with a history of large local reactions to insect stings. Many of the volunteers were subject to unavoidable frequent stings owing to outdoor jobs or hobbies. From that group, Golden selected those whose reactions were marked by extremely large swellings of at least 16 cm - about the size of a football - and winnowed out those who couldn't commit to evaluations that involved live insect stings or the rigorous study schedule.

With a final count of 29 research subjects, Golden subjected them to an initial sting to rigorously measure their response, then separated them into two groups: 19 who would get venom shots once a week for seven to 11 weeks over a summer, and 10 who would get no shots. While the control group members' responses to stings stayed the same, those in the treatment group showed 50 percent less swelling on average.

After the first summer, both groups received venom therapy for up to four years. Following two or more years of treatment, both groups had swellings about 60 percent smaller on average than initial measurements, though the response to treatment varied. Some of the patients had almost complete elimination of their reactions, while others still experienced moderate swelling.

Golden and his team plan to investigate why patients differ in their response. Nonetheless, he notes that this improvement is still enough to warrant a larger trial of the therapy. "We believe these results will lead to broadening the guidelines for using venom therapy," Golden says.

Other researchers who participated in this study include Denise Kelly, R.N., B.S.N., and Robert G. Hamilton, Ph.D., both of Johns Hopkins, and Timothy J. Craig, D.O., of Penn State Hershey Medical Center.