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Subungual Nail Erythrasma Presenting as Melanonychia: A Rare Finding
Jalal Maghfour1, Jennifer Kane2, Leslie Robinson-Bostom2
1Tulane Medical School, Tulane University, New Orleans, Louisiana, USA.
Abstract:
Nail pathology may reflect a wide array of localized and systemic dermatological conditions. Certain nail findings such as melanonychia can create diagnostic challenges even to nail experts. We report a case of a 78-year-old man who presented with melanonychia of the great toe. Nail clipping showed focal melanin deposition, and dermoscopy demonstrated a region of localized erythema in the lunula concerning for possible melanocytic neoplasm. Subsequent nail biopsy showed numerous vertically oriented filamentous bacteria and coccobacilli within the nail plate consistent with a diagnosis of subungual nail erythrasma. Nail erythrasma is a rare entity. Additionally, this case highlights a new clinical presentation of nail erythrasma as melanonychia.
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