Frequency of imported fire ant stings in patients receiving immunotherapy

Background: Imported fire ant (IFA) stings are an important cause of stinging insect hypersensitivity in endemic areas. IFA stings are difficult to avoid, and many studies have shown high field sting rates. No studies report the natural IFA sting rate that patients experience while receiving IFA immunotherapy. Objective: To determine the frequency of IFA stings in patients receiving IFA immunotherapy compared with an aeroallergen immunotherapy control group. Methods: Patients were surveyed by telephone to characterize the frequency of stings, reactions, and attitudes toward IFA avoidance. Results: A total of 23 of 28 patients reported IFA stings during their IFA immunotherapy compared with 16 of 28 patients during their aeroallergen immunotherapy. More of the IFA immunotherapy-treated patients were stung than the aeroallergen immunotherapy patients, which is inconsistent with our hypothesis (χ₂ = 4.139, P <.042). The annualized sting rates between the IFA immunotherapy and aeroallergen immunotherapy groups were similar (1.82 vs 1.72 stings per year, P <.55). The IFA immunotherapy patients were more likely to report any kind of reaction (χ₂ = 9.124, P <.003) compared with the control group. Most patients reported feeling careful to avoid stings. Conclusions: Patients with IFA hypersensitivity treated with IFA immunotherapy do not experience a decreased frequency of stings resulting from attention to sting avoidance. IFA stings are frequent and difficult to avoid. Rush IFA immunotherapy is a good option for many patients to achieve protection quickly.