Laser resurfacing-induced hypopigmentation: Histologic alterations and repigmentation with topical photochemotherapy

BACKGROUND. Hypopigmentation is a relatively common side effect of CO2 lase r resurfacing. Little is known regarding the histologic features of the are as of pigmentation loss. To date, hypopigmentation is considered a permanen t complication of this procedure. OBJECTIVE. To assess the histologic features of hypopigmentation caused by laser resurfacing and to evaluate the efficacy and safety of topical psoral en photochemotherapy. METHODS. Ten patients were included in this pilot study. Four had baseline biopsies performed. Histologic parameters assessed included epidermal melan in, dermal melanophages, perivascular inflammation, Mel-5 immunostaining fo r melanocytes, and dermal fibrosis. Seven patients were created twice a wee k with topical photochemotherapy utilizing 0.001% 8-methoxypsoralen. RESULTS. All of the biopsy specimens demonstrated varying quantities of epi dermal melanin and residual epidermal melanocytes. Mild perivascular inflam mation was evident in two specimens. Superficial dermal fibrosis was noted in all biopsy specimens. Topical photochemotherapy induced moderate to exce llent repigmentation in 71% of the treated patients. Adverse effects were m inimal. CONCLUSION. The results of this investigation suggest that hypopigmentation induced by laser resurfacing map result from a suppression of melanogenesi s rather than destruction of area melanocytes. The preliminary data further suggest that hypopigmentation caused by laser resurfacing can be effective ly treated by topical photochemotherapy.