Melanonychia
Pronunciation: mel-an-oh-NIK-ee-ah
Brown or black longitudinal pigmentation of the nail plate caused by increased melanin deposition, which may be benign or indicative of subungual melanoma.
Full Definition
Melanonychia describes the clinical finding of brown-to-black discolouration of the nail plate resulting from melanin deposition within the nail matrix or plate. It can present as a single longitudinal band (longitudinal melanonychia) or involve the entire nail (total melanonychia). Causes range from physiological melanocyte activation, trauma, and medications to subungual melanoma, making accurate editorial reproduction of the term critical in oncology and dermatology documentation. Editors should not confuse this with subungual haematoma, which has a distinct traumatic aetiology and different clinical appearance. The preferred spelling uses '-ychia' (not '-ycia').
Usage
Usage note: Distinguish clearly from 'subungual melanoma' in clinical notes; melanonychia is a sign, not a diagnosis.
In Context
- "The patient presented with longitudinal melanonychia affecting the right thumbnail, prompting referral for dermoscopic evaluation." — GP referral letter
- "Editors should note that melanonychia is spelled with '-ychia' and should not be abbreviated in patient-facing documents." — Editorial style guide