Squaric acid immunotherapy for warts in children

Background: Warts are a common pediatric skin infection caused by human pap illomavirus (HPV). Spontaneous clearance of warts involves anti-HPV immunit y which may be enhanced by contact sensitizers. Squaric acid dibutylester ( SADBE) is a nonmutagenic sensitizing agent useful for immunotherapy of alop ecia areata. Objective: We hypothesized that SADBE home application might be effective t herapy for warts. Methods: An open-label, retrospective study of 61 children with warts was p erformed. Sensitization with 2% SADBE an the forearm was followed with home application of 0.2% SADBE to warts 3 to 7 nights per week for at least 3 m onths. Results: Complete clearing occurred in 34 patients (58%), with a mean durat ion of therapy of 7 weeks. Partial clearing occurred in 11 (18%), and no re sponse in 14 (24%). Clearance correlated with plantar distribution, wart du ration under 2 years (P < .05), and first-line therapy with SADBE. Mild sid e effects occurred in one third of patients, were limited most commonly to mild erythema at the site of sensitization, and necessitated discontinuatio n of therapy in only 2 patients. Conclusion: SADBE topical immunotherapy is a safe, effective option for hom e therapy of warts in children.