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

Background: Inadvertent Hymenoptera stings reportedly elicit large local re actions 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 progre ssively larger reactions at honeybee sting sites with subsequent stings. Th en, 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 sever e pain. He refused steroid therapy and voluntarily requested venom IT with honeybee-sting challenges to monitor clinical parameters and immunologic ch anges 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 wee ks of edema that involved the entire arm. After rapid escalation of venom I T 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 an d no late-phase induration. Complete loss of any visible reaction at the fi eld sting site resulted after 13 months of maintenance venom IT. A HBV-spec ific IgG antibody level >3.5 mug/mL and IgG/IgE antibody molar ratio >500 p ersisted over the period of venom IT, with venom skin reactivity diminishin g 100-fold. Conclusions: These results support venom IT use in the treatment of Hymenop tera venom-sensitive individuals who experience large local reactions and a re at risk for repetitive inadvertent stings.