Abstract: A child, 2 years and 6 months old,was presented to the doctor for 10 months due to scalp scaly and black dots. The case was once misdiagnosed as 'seborrheic dermatitis’. Wood lamp examination,dermoscopy,fungal fluorescence microscopy and fungal culture on the scalp scaly and hair were carried out. Molecular biological identification was used to identify fungal species. Ultimately, Trichophyton violaceum infection caused black dot ringworm was diagnosed.The patient was cured by taking terbinafine tablets and topical treatment.

Key words: child, black dot ringworm, Trichophyton violaceum, dermoscopy