RESUMO
BACKGROUND: Racial melanonychia striata is a nail plate dyschromia described as a gray coloration of the background in dermatoscopy and hypermelanosis in histology. However, many cases with brown or black coloration of the background in the dermatoscopic examination have been followed. OBJECTIVE: Evaluate racial melanonychia striata dermatoscopical patterns and histological diagnosis in Fitzpatrick skin Types IV, V, or VI population. MATERIALS AND METHODS: 482 Fitzpatrick skin Types IV, V, or VI patients, between 19 and 72 years of age, were clinically evaluated and underwent nail plate dermatoscopic examination. Fifty-eight patients presenting melanonychia striata and dermatoscopic patterns with brown or black coloration of the background were submitted to a nail matrix biopsy. When occurring in more than 1 digit, biopsy was performed in the lesion with the darkest coloration presented in dermatoscopy. RESULTS: All skin Types IV, V, or VI patients who had melanonychia striata, with brown or black coloration of the background in the dermatoscopic examination, revealed histopathological analysis compatible with hypermelanosis. CONCLUSION: Racial melanonychia in skin Types IV, V, or VI patients, resulting from hypermelanosis, may present brown or black coloration of the background in the dermatoscopic examination.