Examining the Efficacy and Safety of Squaric Acid Therapy for Treatment of Recalcitrant Warts in Children

Abstract The objective of the study was to determine the safety and efficacy of squaric acid dibutyl ester ( SADBE ) therapy on the treatment of recalcitrant warts in children. This retrospective chart review examined 72 patients treated using SADBE from July 2002 to December 2012. Patients were followed for 6 months to 11 years. Patients were treated at a pediatric dermatology outpatient clinic at the University of North Carolina at Chapel Hill. Seventy‐two children with verrucae who failed initial treatment for warts were selected for the study. Full long‐term follow‐up was obtained in 48 patients. Four patients discontinued the use of SADBE because of adverse effects. The primary study outcome was efficacy of SADBE treatment. Adverse effects, dosages administered, type of wart, other cutaneous disease present, and level of immunosuppression were measured. Forty of 48 (83%) patients in whom treatment outcomes could be obtained reported complete resolution of their warts. Seventy percent of patients used a maximum concentration of 0.4% SADBE and 60% of patients reported no adverse effects. The majority of patients treated with SADBE reported complete resolution of warts. Most patients reported no adverse effects even while receiving doses as high as 2% daily. This study shows that SADBE is a safe and effective treatment for recalcitrant warts in children.