Research Letter Examines Effects Of Chemical Sunscreen On UV Radiation In Melanocytic Nevi

Date: May-08-2013JAMA Dermatology Study Highlights

In a research letter, Rainer Hofmann-Wellenhof, M.D., of the Medical University of Graz, Austria, and colleagues examined the effects of a chemical sunscreen on UV-Induced changes of different histological features in melanocytic nevi. (Online First)

Researchers selected 26 melanocytic nevi from 26 patients (12 male and 14 female, mean age, 31 years; median age, 31.5 years) in 2003. A sunscreen with sun protection factor (SPF) of 6.2 (containing UV-A and UV-B filter) was applied exactly to one-half of each nevus by using a tape to avoid contamination of the other half. Clinical and dermoscopic images were acquired using a digital camera equipped with a polarized dermatoscope at baseline (day 0) before sunscreen application and UV irradiation and at day 3 and day 7 when the nevus was excised.

Dermoscopy at day 3 showed an increase of erythema and a more pronounced pigment network in the unprotected halves but without statistical differences compared with the protected halves. At day 7 researchers observed an increase of brown to black globuli, brown dots, bluish white veil, atypical network, and increased vessels in both protected and unprotected halves without statistical differences between the 2 halves. The HMB-45 stain resulted in significantly stronger staining in the unprotected halves compared with the protected ones, the study finds.

"In summary, we extended the dermoscopic findings observed by Carrera et al into the field of solar-simulated UV radiation, and we agree that not all UV-induced changes are confined to unprotected areas," the authors notes.

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