[Skin nodules and ulcers of the limbs in a patient with rheumatoid 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 immunocompromised patients and in the differential diagnosis of vasculitis.