Monodactylous Longitudinal Melanonychia in Pediatric Skin of Color: A Case Series and Review.

Introduction: Longitudinal melanonychia, a pigmented longitudinal streak on the nail, is a common clinical finding that may be associated with subungual melanoma with varying presentation depending on race and skin tone. It has been long reported that darker skinned ethnicities have a higher prevalence of longitudinal melanonychia in the US population (e.g., African Americans with 77% prevalence) [Indian J Dermatol. 2021;66(4):445], but unfortunately, there are limited studies exclusively looking at longitudinal melanonychia in pediatric patients of color.

Case presentation: In this case series, we review the current literature and report the findings of 8 cases of longitudinal melanonychia in children with skin types IV or greater. Out of the 8 cases identified, only 4 returned to the clinic for monitoring (n = 4), and there was an average of 20.8 months between the initial and final visits. Of the patients that returned for follow-up, 2 showed no relevant changes in the nail pigmentation, 1 showed fading of the band, and 1 patient showed enlargement of the band to involve the whole nail.

Conclusion: Although many sources recommend a conservative approach to treatment that involves monitoring and follow-up, our findings indicate that a wait-and-see method cannot be applied to all cases in the pediatric population due to disruptions in continuity of care. An individualized approach considering such factors should be employed for each patient, and certain high-risk features of the ABCDEF nail melanoma model may be relevant in pediatric cases.