Diagnostic criteria for and clinical review of melanonychia in Korean patients.

BACKGROUND: Melanonychia may be the presenting sign of ungual melanoma. However, there are insufficient basic clinical data for melanonychia in Korean patients.

OBJECTIVE: We sought to identify basic clinical data and devise a classification algorithm for melanonychia.

METHODS: In all, 275 patients with melanonychia who visited our clinic from January 2002 to August 2014 were included in this study. We reviewed medical records, clinical and dermoscopic photographs, and histopathologic findings and we assessed demographics (eg, age); medical (eg, systemic diseases), family, and trauma (eg, nail biting) history; and physical findings (eg, affected number and site).

RESULTS: The 5 most common causes of melanonychia in Korean patients were subungual hemorrhage (29.1%), nail matrix nevus (21.8%), trauma-induced pigmentation (14.5%), nail apparatus lentigo (11.6%), and ethnic-type nail pigmentation (8.0%). Melanoma was diagnosed in 6.2% of patients. Ethnic-type nail pigmentation was commonly identified.

LIMITATIONS: This is a retrospective study from a single center.

CONCLUSION: We propose a revised diagnostic algorithm for melanonychia to assist in the evaluation of this condition.