Tankersley MS, Walker RL, Butler WK, Hagan LL, Napoli DC, Freeman TM. J Allergy Clin Immunol. 2002;109:556–562
Purpose of the Study.
To evaluate the safety and efficacy of rush immunotherapy (RIT) with imported fire ant (IFA) whole body extract and to determine if prophylactic pretreatment with antihistamines and steroids reduces the rate of associated systemic reactions.
Patients, 18 to 65 years old, with IFA hypersensitivity were enrolled from August 1996-June 1999. Hypersensitivity was defined as history of systemic reaction to IFA sting and positive IFA skin test result.
IFA-allergic patients enrolled in the RIT protocol were randomized in a double-blind manner to one of 2 prophylaxis regimens: 1) placebo pretreatment and 2) premedication with twice-daily treatment of terfenadine 60 mg, ranitidine 150 mg, and prednisone 30 mg. The pretreatment was begun 2 days before protocol start and continued through the evening of the last RIT dose. The RIT protocol included hourly injections on days 1, 2, 8, and 15. Protocol efficacy was determined on day 22 using a pair of IFA sting challenges 2 hours apart.
Fifty-eight patients (age range: 18–49 years) entered the 2-day RIT. Only 5.2% experienced mild systemic reaction during the protocol. There was no statistical difference between the 2 premedication groups (3.6% active vs 6.7% placebo; P = .87). Efficacy was 98.2% in 56 patients undergoing sting challenge.
The authors conclude that RIT is both safe and efficacious for adults patients that have IFA hypersensitivity. The rate of systemic reactions is low and premedication with a combination of H1 and H2 antihistamines and oral corticosteroids is not necessary.
One limitation of traditional immunotherapy is the long build-up period required for desensitization. This not only serves to discourage some patients but provides an additional hazard for patients with hypersensitivity reactions to insect venom and continual exposure. These authors have effectively demonstrated that RIT is safe and efficacious in adult patients. Although encouraging, additional studies are needed in children to confirm the same safety and efficacy parameters in fire ant-hypersensitive individuals.