Intraoperative onychoscopy and histopathological correlation of red lunula in nail lichen planus: a case series.

The lunula is the white half-moon-shaped area located at the base of the fingernails and toenails, and is the only visible part of nail matrix. Red lunula can present as a complete form (the whole lunula is red), incomplete form (only the proximal lunula is red) or mottled form. Red lunula has been associated with a number of dermatological and systemic conditions. It is one of the less common manifestations of nail lichen planus (LP). However, the pathogenesis of the red lunula is not yet clear. We present a series of six patients with nail LP presenting with red lunula, and describe the findings of intraoperative onychoscopy and histopathology in an attempt to understand the pathogenesis underlying the condition.