Malassezia Fungi Are Specialized to Live on Skin and Associated with Dandruff, Eczema, and Other Skin Diseases

Malassezia is a monophyletic genus of fungi found on the skin of 7 billion humans and associated with a variety of conditions, including dandruff, atopic eczema (AE)/dermatitis, pityriasis versicolor, seborrheic dermatitis, and folliculitis ([1,2]; Figure 1). In immunocompromised hosts Malassezia can also cause systemic infections. There are 14 currently recognized species of Malassezia, eight of which have been associated with humans, four of these commonly [3]. Malassezia spp. are Basidiomycetous fungi, as are most species of fungi readily seen on a walk through the forest. Among the Basidiomycota, only Malassezia and Cryptococcus are frequent human pathogens. However, their adaptations to humans are presumed to be independent: Malassezia’s closest relatives are plant pathogens: the smuts and rusts, whereas the closest relatives for Cryptococcus pathogenic species are fungal saprotrophs associated with trees and insects. We summarize here a cellular and molecular description of some interactions of Malassezia with humans and speculate on properties (release of allergen-containing nanovesicles, mating) that may be critical to Malassezia virulence.