Background: Exposure to UV radiation can lead to clinical, histologic, and ultrastructural changes in acquired melanocytic nevi.
Objective: We investigated whether UVB therapy can induce changes in melanocytic nevi detectable by dermoscopy.
Methods: Eighty acquired melanocytic nevi of 13 patients (10 females, 3 males; mean age, 28 years; range, 13 to 62 years) undergoing UVB therapy were documented under standardized conditions by means of a Dermaphot apparatus before and at the end of suberythemal UVB therapy. The mean duration of therapy was 8 weeks (range, 2 to 17 weeks) and the mean total UVB dose was 1120 mJ/cm2 (range, 247 to 2771 mJ/cm2). During UV irradiation, 40 nevi were left unprotected and 40 nevi were protected from UV exposure in a randomized manner. Color dermoscopic images of nevi before and after UVB therapy were projected side by side and examined blindly by five investigators. Fifteen different features were evaluated in the nevi.
Results: Unprotected nevi became more irregular (p < or = 0.01) and darker brown (p < or = 0.03) by the end of the therapy, whereas the protected nevi showed no significant changes.
Conclusion: Suberythemal UVB therapy can lead to changes in the dermoscopic image of acquired melanocytic nevi, presumably by activating melanocytes.