Background: Cutaneous warts are an extremely common problem, whose eradication can be challenging. Topical PDT involves applying a porphyrin precursor, 5-aminolevulinic acid (ALA) or methyl aminolevulinate (MAL) to the affected area. ALA-PDT has been well documented to be successful in the treatment of recalcitrant warts. PDT has a limited role in the treatment of thicker lesions because the photosensitizer does not penetrate keratotic lesions well, though this is vehicle dependent.

Objective: The aim of this study was to evaluate the efficacy and safety of curettage + microneedling + ALA-PDT for the treatment of resistant acral warts. We hypothesized that microneedling may increase the efficacy of PDT, providing a channel to deliver the ALA to deeper areas of warts.

Methods: Our study was carried out between November 2017 and July 2018. Eligible participants had one or more resistant plantar or palmar warts. Thirteen patients were recruited. They underwent a thorough curettage, followed by the application of 5-ALA 10% cream on the wart, and by microneedling. Later, the pricked skin was covered for three hours by an occlusive polyurethane dressing, and finally irradiated with a red-light source. Patients performed one session every three weeks for a total of three cycles.

Results:After 3 treatments of curettage + microneedling + ALA-PDT, 11 patients (84.6%) showed complete remission (defined as complete disappearance of their warts). One patient (7.7%) showed partial remission (defined as greater than 50% decrease in the wart area) after 3 sessions; this patient needed other 2 sessions to achieve complete remission. The mean follow-up period after healing was 4.3 months. Adverse effects were recorded.

Conclusion: We have demonstrated, for the first time to our knowledge, that the combination of curettage + microneedling + topical ALA-PDT may offer an effective and safe alternative for the treatment of acral resistant warts, even when PDT alone has already been insufficient.