Case report of venom immunotherapy for a patient with large local reactions.

BACKGROUND

Inadvertent Hymenoptera stings reportedly elicit large local reactions in up to 17% of the general population. Current practice parameters do not recommend venom immunotherapy (IT) for these cases.

OBJECTIVE

The goal of this case study was to investigate the clinical and immunologic consequences of venom IT in a newly sensitized individual with large local reactions using an intentional sting challenge before and after treatment to document changes in reaction severity.

METHODS

A 47-year-old man became honeybee venom (HBV)-allergic with progressively larger reactions at honeybee sting sites with subsequent stings. Then, a sting on his forefinger produced a large (62 cm) local reaction with swelling throughout the arm that persisted for more than 4 weeks with severe pain. He refused steroid therapy and voluntarily requested venom IT with honeybee-sting challenges to monitor clinical parameters and immunologic changes in his skin and serum before and 7 months post-HBV maintenance IT.

RESULTS

A single pre-IT bee sting challenge produced an 11.4-cm wheal with 13-cm erythema at the sting site after 15 minutes, followed by several weeks of edema that involved the entire arm. After rapid escalation of venom IT to maintenance in 7 weeks, a post-maintenance IT sting challenge with two honeybees produced a 3-cm diameter erythema with no wheal at 15 minutes and no late-phase induration. Complete loss of any visible reaction at the field sting site resulted after 13 months of maintenance venom IT. A HBV-specific IgG antibody level >3.5 microg/mL and IgG/IgE antibody molar ratio >500 persisted over the period of venom IT, with venom skin reactivity diminishing 100-fold.

CONCLUSIONS

These results support venom IT use in the treatment of Hymenoptera venom-sensitive individuals who experience large local reactions and are at risk for repetitive inadvertent stings.