Pain induced by photodynamic therapy of warts

Abstract

Background: Photodynamic therapy with topical 5-aminolevulinic acid (ALA), followed by irradiation with red light (ALA-PDT), is used for non-melanoma skin cancer and other dermatological diseases. Pain during and after light exposure is a well-known adverse advent that may be a limiting factor for treatment, particularly, in viral warts.

Methods: To assess the pain induced by ALA-PDT, we asked 45 patients enrolled in a randomized, placebo-controlled trial with six consecutive ALA- and placebo-PDT treatments for recalcitrant foot and hand warts to fill in questionnaires about pain immediately and 24 h after each treatment.

Results: Immediately and 24 h after each of the six treatments, pain intensity was significantly higher in warts treated with ALA-PDT than in warts treated with placebo-PDT (P<0.028). Severe or unbearable pain was reported from a median of 17% (6-31%) of the ALA -treated warts and from a median of 2% (0-15%) from the placebo-treated warts immediately after the treatments. With increasing treatments, no significant change in pain intensity was observed and no significant relation was found between the pain intensity and the relative change in wart area. The pain was primarily characterized as burning and shooting. The pain lasted about 30 h (range: 1-96 h).

Conclusion: We conclude that pain induced by ALA-PDT is of such intensity in about one-fifth of the warts that pain relief is indicated.