Key message
Tinea nigra is a superficial and asymptomatic fungal infection
A 13-year-old girl presented with a pigmented lesion on her left palm with a quadrangular shape measuring 2 × 2 cm (Fig 1). The lesion, which appeared 2 years before, after a trip to a Greek island, was interpreted as melanocytic by other dermatologists.
Dermoscopy showed a patch with a weak pigmentation composed of thin bundles of spicules that were arranged in a parallel ridge pattern (Fig 2).
The microscopic examination with potassium hydroxide showed ramified and brownish spores and hyphae and 3 weeks later the culture with Sabouraud dextrose agar revealed dark-colored colonies composed of oval and fusiform cells identified as Hortaea werneckii (Fig 3). We therefore made the diagnosis of tinea nigra. The patient was treated with isoconazole 1% cream 2 times daily for 3 weeks, achieving a complete remission. Tinea nigra is a superficial and asymptomatic fungal infectionKey message
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Conflicts of interest: None declared.