Nocardiosis in a patient with pemphigus foliaceus treated with rituximab

Rituximab is a chimeric human/murine monoclonal anti-CD20 antibody. This agent is an effective therapeutic option in severe types of pemphigus. However, rituximab may cause opportunistic infections if used in immunosuppressed patients. We reported a case of diffuse Nocardia infection following rituximab treatment in pemphigus foliaceus. Rheumatoid arthritis protocol applied in our patient. Rituximab was used at a dose of 1000 mg every 2 weeks. Because the disease was not adequately controlled, rituximab treatment was administered six times every 15 days. One week after the sixth dose of the rituximab, she presented lassitude and multiple palpable masses in soft tissue of the upper extremity. Thereafter, the aspirate culture of the abscess on the left shoulder was taken and confirmed to be disseminated nocardiosis. She was treated with linezolid and meropenem for 1 month; however, amikacin was added because the patient did not respond adequately to linezolid and meropenem therapy. The patient died of cardiac arrest because of her comorbidities. In this case, prolonged administration of rituximab therapy may have caused the development of nocardiosis. Therefore, all patients should have a sensible balance of risk and benefit, considering the use of rituximab.