Alternaria species are common plant pathogens, but a rare cause of human infection. We present a patient with cutaneous alternariosis that revealed a relapse of an old case of Cushing's disease. Immunosuppression following the excessive glucocorticoid production seemed to contribute to the development of dermatosis. We also present a review of the literature on the association of Cushing's disease and cutaneous alternariosis. Our case is unique because the ketoconazole therapy that we used was successful in the treatment of both diseases.