Nonsegmental vitiligo follows Blaschko's lines and embryonic pigmentary segments

BACKGROUND: Pathogenic mechanism that determines the localization of vitiligo patches and thus a patterned distribution in patients with nonsegmental vitiligo has remained poorly elucidated. A distributional similarity of the vitiligo patches with Blaschko's lines has been documented in patients with segmental vitiligo, both isolated segmental vitiligo and mixed vitiligo but never in cases of nonsegmental vitiligo. METHODS: Distribution of nonsegmental vitiligo patches on face and neck regions was assessed and compared with Blaschko's lines and also with embryonic pigmentary segments on the face. RESULTS: This study has documented distributional similarity of the nonsegmental vitiligo patches on face and neck with Blaschko's lines and the "embryonic pigmentary segments" among 154 (58.6%) cases. Patches around the palpebral and other fissures like periorbital, perinasal, perioral, and periaural were more common. In addition to the vitiligo patches, the spared areas were also found to respect the embryonic segmental outlines and follow the Blaschko's lines. CONCLUSION: Distributional pattern of the individual nonsegmental vitiligo patches along the Blaschko's lines and embryonic pigmentary segments suggests that mosaicism might control the susceptibility to the disease process in a patterned manner. LIMITATION: No genetic testing could be performed to confirm the hypothesis. Evaluation of nonsegmental vitiligo was done only on the face and neck areas.