Mycobacterium marinum Infection in a 45-Year-Old Woman

A 45-year-old woman noted painless, red, crusted papules on the hand. This was followed by the appearance of deep, slightly tender red nodules on the arm and ipsilateral axillary adenopathy. The patient had a home aquarium. There was no history of trauma to the affected hand or arm.

Key point: The history and clinical appearance are typical for the “sporotrichoid” spread of an infection. This most notably occurs with sporotrichosis, but may also been seen in conjunction with atypical mycobacterial infection, leishmaniasis, and tularemia, as well as other infections. Assuming that the patient helped provide maintenance for the aquarium, atypical mycobacterial infection should be highly suspect. In fact, tissue obtained from both the hand and arm lesions grew Mycobacterium marinum. Treatment: Oral minocycline (200 mg/d) was given until the lesion resolved in 10 weeks.

Note: Clarithromycin is an alternative antibiotic treatment. Use of adjunctive thermotherapy (periodic application of heat) may be considered in severe or recalcitrant cases.