Mycobacterium marinum infection causing extensive tissue destruction in a hypoxic COPD patient

We report a skin Mycobacterium marinum infection presenting as wide ulcerative lesions of the arm (4 cm for the widest) in a hypoxic COPD patient who takes 4 mg methylprednisolone daily and higher doses during exacerbations. Diagnostic delay as well as glucocorticoid use could be responsible for the extension of the lesions. Clinical resolution occurred after three months of antibiotic therapy. Extensive ulcerative lesions are uncommon in Mycobacterium marinum infection in an immunocompetent host. This case emphasizes the potential and unusual harmful effect of long-term glucocorticoid therapy used in obstructive lung disease on the spread of Mycobacterium marinum infection.