Sporotrichoid Nocardiosis in an Immunocompetent Patient: A Case Report

Nocardia spp. rarely cause infection in humans and are most common in the immunocompromised population. Pulmonary nocardiosis is the most common presentation. Cutaneous involvement is usually acquired after direct contact. A 71-year-old healthy male patient presented with a non-healing wound in his left leg that had appeared two weeks before. The patient had been engaged in yard work after a hurricane. He developed pain in the left calf, later noticing a small wound attributed to an insect bite or a thorn prick. The lesion exhibited increasing surrounding erythema, purulent discharge, and escalating pain. He completed a course of doxycycline prescribed by his primary care physician, but it did not lead to any improvement. The physical examination revealed swelling in the left leg with an ulcer surrounded by erythema. A combination of linezolid and ciprofloxacin was initiated without improvement. Shortly after, lymphangitis was noted, raising concern for sporotrichosis. Antifungal treatment with itraconazole was empirically initiated while continuing linezolid and ciprofloxacin for suspected superimposed bacterial infection. A wound culture revealed beaded gram-positive rods, which were subsequently identified as Nocardia brasiliensis. The previous antibiotic regimen was discontinued, and trimethoprim/sulfamethoxazole was initiated; he completed a 12-week course and recovered successfully. Nocardiosis remains a rare entity and is even rarer in the immunocompetent, in which cutaneous presentations are more common than pulmonary or disseminated forms. This resonates with the case presented who was a healthy male patient. Cutaneous nocardiosis clinical presentation varies widely, the case presented progressed to lymphocutaneous involvement, and it resembled sporotrichosis. The indolent course and the lack of response to traditional therapies suggested a different and rare etiology in our case. Results of cultures usually take several days as Nocardia species are slow-growing organisms, which can lead to a delay in diagnosis. Cotrimoxazole monotherapy is the first-line treatment in cutaneous presentations.