A case of tinea nigra caused by Hortaea werneckii infection and literature review
Objective To explore the clinical characteristics and epidemiological status of tinea nigra,and review related literature to improve clinicians'understanding of the disease.Methods Clinical data of an adult patient with tinea nigra was summarized,and the results of mycological dermoscopic examination and molecular identification were presented.In addition,the literature related to tinea nigra was reviewed.Results A brown patch was seen on the right palm.Dermoscopy showed fine dotted and filamentous structures under a brown background.Microscopic examination showed sporulating hyphae and conidia with thick walls.The fungi were identified as Hortaea werneckii by molecular technique.A total of 31 cases of tinea nigra in 19 publications(including this case with a total of 32 cases)were reported in China and 54 papers(105 cases)outside of China.Conclusions Tinea nigra mainly occurs on the palms of children in coastal areas.Non-invasive dermoscopy and fluorescence microscopy can be primary approaches to examine fungal infection,and the pathogenic fungi can be identified by molecular approach.It can be easily misdiagnosed as malignant melanoma.Clinicians should be aware of this disease to avoid unnecessary biopsy or resection.