Cutaneous Cryptococcosis

Cutaneous cryptococcosis is classified either as primary or secondary based on the route of infection. The disease can also be classified either as localized cutaneous cryptococcosis or cutaneous manifestations of disseminated cryptococcosis. However, from a physician's point of view, whether lesions are localized to the skin or are disseminated/systemic is more important than the route of infection. The Clinical Practice Guidelines for Diagnosis and Treatment of Cryptococcosis, which was established in 2019 by the Japanese Society for Medical Mycology, adopted the latter classification. Localized cutaneous cryptococcosis is defined as a condition in which lesions are confined within a limited part of the skin, not systemically disseminated at the same time, and are associated with neither cryptococcal fungemia nor antigenemia. This type of cutaneous cryptococcosis is uncommon in Japan. Only 65 cases were reported during the 50-year study period from 1968 to August 2018, with the patients divided into two groups: immunocompromised patients (n=44, 68%) and immunocompetent patients (n=21, 32%). None of the patients were infected with the human immunodeficiency virus (HIV). Localized cutaneous cryptococcosis can also occur in non-HIV-infected patients and well-appearing individuals, therefore, it is considered an important infection in routine dermatology practice. Here, we outline the classification, diagnosis, and treatment of cutaneous cryptococcosis and present a summary of cutaneous cryptococcosis cases reported in Japan.