Variation of melanin levels in the skin in areas exposed and not exposed to the sun following winter and summer

Introduction The pigment mainly responsible for the color of the skin, melanin is directly influenced by exposure to sunlight. Objective: The present study assessed the effects of solar radiation on the levels of melanin in areas exposed and not exposed to the sun, taking into consideration the seasonality of exposure. Methods: Melanin levels were evaluated on the forehead, sacral region, and forearm, in the post-summer and post-winter periods, using spectrophotometry. Results: The levels of melanin after winter were lower than those after summer in the forehead (168.1 vs. 177.0), sacral region (132.0 vs. 140.4), and forearm (218.7 vs. 260. 4), with a statistically significant reduction only in the forearm (p<0.0001).Additionally, erythema was significantly less intense in the forearm and forehead (p<0.0001 and p=0.002) after winter than after summer. Conclusion: The significant reduction of melanin levels in the forearm after winter reinforces the influence of seasonality on skin pigmentation changes to body areas exposed to the sun without protection.The small variation in the levels of melanin found in the unexposed area (sacrum) confirms that the effect of exposure to the sun on the levels of melanin is predominantly local. Increased production of melanin is directly related to local exposure to UV rays.

Keywords: MELANINS; ERYTHEMA;SOLAR RADIATION; PIGMENTATION.