PRIMARY CUTANEOUS NOCARDIA INFECTION DUE TO NOCARDIA ASTEROIDES

Abstract

A 34‐year‐old white man was admitted to the hospital for treatment of cyclosporine toxicity. He was referred to the dermatology service for the evaluation of two lesions that had been present for 4 weeks on the dorsum of his left hand. The patient stated that he had cut his hand on a fence and later cleaned his aquarium two weeks before the skin lesions appeared. The past medical history was significant for a cadaveric renal transplant in 1984 for renal agenesis of the left kidney and obstructive nephropathy of the right kid‐ney. His oral medications included methylprednisolone, dil‐tiazem, ranitidine, cyclosporine, and ketoconazole. The recent addition of ketoconazole for oral thrush was felt to have caused the cyclosporine toxicity.The patient was cushingoid in appearance with promi‐nent generalized hypertrichosis. The vital signs and the chest examination were normal. Skin examination revealed a 6‐mm tense vesicle with surrounding erythema with an adjacent 5‐mm firm linear papule (Fig. 1). There was no lymphadenopathy. Both lesions were biopsied, hemisec‐tioned, and sent for routine light microscopy and for fungal, atypical mycobacterial, and bacterial cultures.Laboratory studies were significant for a blood urea ni‐trogen of 56 mg/dL, creatinine of 2.6 mg/dL, WBC of 13,100/mm13, and a cyclosporine level of 2333 ng/mL (thera‐peutic level 100–300 ng/mL). X‐ray of the left hand showed no abnormality. Chest x‐ray and computerized axial tomog‐raphy scan revealed a widened superior mediastinum sec‐ondary to mediastinal lipomatosis. Tissue cultures grew Nocardia asteroides. Bacterial and mycobacterial cultures, including atypical mycobacteria, were negative.The biopsy showed a mixed cellular infiltrate with scat‐tered multinucleated giant cells and focal microabscesses. Brown and Brenn stain showed gram‐positive filamentous organisms.A modified Fite stain (Fig. 2) demonstrated acid‐fast filamentous organisms. The patient was diagnosed as having primary cutaneous nocardiosis with no evidence of dissemination. He was treated with trimethoprim sulfamethoxazole (TMP/SMX), one tablet orally four times daily, with resolution of the skin lesions within 3 weeks, but the patient developed neurolog‐ic toxicity and elevation of his serum creatinine with this therapy. He was unable to tolerate a lower dose of TMP/SMX and the medication was changed to sulfisoxazole 500 mg orally four times daily, with plans to continue the treatment for 12 months.There has been no recurrence after almost 12 months of therapy.