Melanonychia
Pronunciation: mel-uh-no-NIK-ee-uh
Longitudinal or diffuse brown-to-black pigmentation of the nail plate caused by melanin deposition, requiring careful differentiation from subungual melanoma in clinical documentation.
Full Definition
Melanonychia describes nail pigmentation arising from activation or proliferation of melanocytes in the nail matrix. It may be longitudinal (a single brown-black streak—'longitudinal melanonychia') or total. Causes range from benign racial/ethnic melanocyte activation and drug effects to melanocytic naevi and subungual melanoma. In dermatology reports and dermoscopy documentation, editors will encounter the compound forms 'longitudinal melanonychia' and 'melanonychia striata'. The term must not be confused with 'subungual haematoma', which is a common clinical and editorial error. Correct hyphenation of the compound adjective is 'nail-matrix melanocytes' when used attributively.
Usage
Usage note: Specify 'longitudinal melanonychia' or 'total melanonychia' where the pattern is stated. Do not use as a synonym for subungual haematoma; the two have different aetiologies and management pathways.
In Context
- "Dermoscopy of the longitudinal melanonychia showed a homogeneous brown band without atypical features, suggesting benign melanocyte activation." — Dermoscopy report
- "The editor queried whether 'melanonychia' had been confused with 'subungual haematoma' given the clinical context described." — Copy-editing query