Diagnosis and treatment of lymphocutaneous dermatosis caused by Nocardia brasiliensis: a case report.

Cutaneous nocardiosis is a skin disease mainly caused by Nocardia brasiliensis and Nocardia asteroides. Here, we report a rare case of lymphocutaneous dermatosis in an 87-year-old Chinese man infected with Nocardia brasiliensis. An 87-year-old Chinese man presented at our hospital after suffering erythema, nodules, abscesses, ulceration, and pain in the left upper limb for 10 days. The patient was initially misdiagnosed as lymphocutaneous sporotrichosis. The results of gram staining, acid-fast staining, mass spectrograph revealed Nocardia brasiliensis and 16S ribosomal RNA (16S rRNA) sequencing of samples showed that the patient had a Nocardia brasiliensis infection. Anti-infective therapy with sulfamethoxazole combined with amoxicillin clavulanate potassium was administered for 10 days, followed by sulfamethoxazole alone for 20 days. After 30 days of treatment, the abscess was treated with repeated pus extraction, debridement of erosion and ulcer, wet compress of povidone iodine solution and spectrum of multi-source instrument. The redness and swelling had subsided, and purulent secretion and ulceration had decreased. Lymphocutaneous nocardiosis can easily be misdiagnosed as sporotrichosis based on its clinical manifestations. However, mass spectrometry analysis showed Nocardia brasiliensis according to the fingerprint of the bacteria and 16S rRNA sequencing to identify bacterial DNA can assist with making a diagnosis. For patients with Nocardia brasiliensis, sulfamethoxazole combined with amoxicillin clavulanate potassium is an effective anti-infective treatment.