Cryptococcosis in the Apparently Immunocompetent: A Shifting Landscape?

Abstract

To comprehensively review clinical, diagnostic, and therapeutic data on the global epidemiology of cryptococcosis in apparently immunocompetent patients with no or only a few minor medical conditions who were previously healthy. While cryptococcosis is often regarded as a rare presentation in presumably healthy individuals, a substantial and increasing number of cases occurring in this group of patients is evident. However, studies focusing exclusively on cryptococcal infection in so-called immunologically normal patients are lacking. In the last decade, 382 cases of cryptococcosis in apparently immunocompetent hosts were reported from 45 countries. Patients were mostly men (66.5%) with an average age of 44 years (range 0 to 86 years). Central nervous system (CNS) involvement was most frequent, followed by disseminated and pulmonary infection. Most patients survived (84.8%). Diagnosis included microscopy, culture, and cryptococcal antigen detection. The species was reported in 271 cases, mainly C. neoformans (59.4%) and C. gattii (36.5%). Amphotericin B, alone or in combination, was mostly used for CNS involvement, whereas fluconazole alone was mostly used for other presentations. This descriptive review highlights that cryptococcosis in the seemingly healthy host is no longer an uncommon etiology and that the epidemiology of this mycosis is a changing landscape.