Abstract: Primary cutaneous nocardiosis is a rare infectious disease caused by Nocardia species directly infected skin and subcutaneous tissue. The clinical manifestations are varied, and it is easy to be misdiagnosed. A patient presented with erythema, nodules, abscesses and ulcers on the left forearm with a large amount of purulent discharge for 2 weeks. Cultures of biopsy samples grew yellow-white colonies that were identified as Nocardia brasiliensis. The patient recovered after 50 days of oral treatment with trimethoprim-sulfamethoxazole (TMP-SMX).

Key words: primary cutaneous nocardiosis, Nocardia brasiliensis, TMP-SMX