Phaeohyphomycosis due to Alternaria species in transplant recipients

Alternaria species are members of a heterogeneous group of dematiaceous fungi that rarely cause opportunistic infections in transplant recipients. During a 20-year period from 1989 to 2008, 8 solid organ transplant recipients (63% males; median age, 48 years) developed Alternaria species infections at the Mayo Clinic. All patients were highly immunocompromised as evidenced by their receipt of multiple transplants, treatment of acute and chronic allograft rejection, and occurrence of other opportunistic infections. All patients presented with non-tender erythematous or violaceous skin papules, nodules, or pustules in exposed areas of the extremities. No case of visceral dissemination was observed. Itraconazole was the most common drug used for treatment, although voriconazole, posaconazole, and caspofungin could potentially be useful based on our limited clinical data and in vitro antifungal susceptibility testing. One patient was treated with voriconazole, while another patient who was refractory to itraconazole had rapid resolution of lesions after the addition of caspofungin. Attempts at antifungal therapy alone were unsuccessful; all patients eventually required surgical excision of lesions. In conclusion, Alternaria species are rare but increasingly recognized opportunistic infections among highly immunocompromised transplant recipients. Wide excisional surgery combined with prolonged systemic antifungal therapy and reduction in immunosuppressive regimens provided the best chance of cure. Although itraconazole remains the most common drug for treatment, this case series highlights the potential clinical utility of caspofungin, voriconazole, and posaconazole as alternative regimens.