Most warts on the hands and feet respond to conventional topical treatments plus paring. Approximately 30 percent, however, are still present three months after initial therapy. Stender and colleagues evaluated the efficacy of therapy developed for treatment of basal cell carcinomas and actinic keratoses in the treatment of recalcitrant warts.

The 45 adult patients studied were referred to a dermatology clinic because of failure to respond to first-line wart treatment. Patients who were immunosuppressed, pregnant or lactating were excluded from the trial. All warts were numbered and pared to visualization of blood vessels. Each wart was then treated with topical 5-aminolevulinic acid (ALA) or a placebo cream of identical appearance and smell. After four hours under an occlusive hydrocolloid dressing, all warts were irradiated with a red light source using wavelengths ranging from 590 to 700 nm. Treatments were repeated after one and two weeks. Patients were reassessed at week 7. If necessary, treatment was reapplied. Patients were assessed again at weeks 14 and 18. Photographs were taken as part of each assessment. Wart area on the photographs was one of the primary outcome measures. Patients also recorded any pain or adverse events attributed to treatment.

The median age for the group was 37 years, and the median duration of warts was 55 months. The placebo and active treatment groups were similar in all important variables. At week 14, one half of the warts treated with ALA had vanished, compared with 35 percent in the placebo-treated group. This difference and the difference at 18 weeks were statistically significant. The warts that remained showed significantly greater reduction in area if treated with ALA than if treated with placebo. Patients treated with ALA reported greater pain after treatments, but the groups did not differ in any other reported adverse event.

The authors conclude that ALA enhanced with irradiation provided an effective therapy for resistant warts but was associated with greater local pain than placebo treatment.