Hautknoten und Ulzera der Extremitäten bei einem Patienten mit rheumatoider Arthritis

CASE HISTORY: While being treated with corticosteroids and methotrexate for rheumatoid arthritis, a 63-year-old man developed livid nodules on his lower arms, hands and feet, as well as fever, necrotizing skin ulcers and rupture of a finger extensor tendon. INVESTIGATIONS: No vasculitis was found in a biopsy of one of the nodules on the lower arm. Fast growing mycobacteria, classified as M. marinum by PCR, were cultured from wound swabs. TREATMENT AND COURSE: The lesions healed on administration of ciprofloxacin, ethambutol and clarithromycin as well as local treatment. CONCLUSION: Cutaneous lesions of an atypical mycobacterial infection are often misdiagnosed. This is especially so in immu…