Malassezia species are dependent on exogenous lipids because they lack fatty acid synthase genes, except M. Depending on sampling technique and diagnostic methods they have been isolated from 30 to 100% of newborns ( Ayhan et al., 2007 Nagata et al., 2012). Malassezia colonize the human skin after birth and must therefore, as a commensal, be normally tolerated by the human immune system. They interact with almost all the cellular constituents of normal epidermis, including keratinocytes, Langerhans cells, melanocytes as well as the host immune system, both directly but also through chemical mediators ( Glatz et al., 2015 Grice and Dawson, 2017). It is the most prevalent fungal genus of the healthy skin, but these yeasts also demonstrate a pathogenic potential where they can, under appropriate conditions, invade the stratum corneum. The genus Malassezia belongs to the phylum Basidiomycota (class Malasseziomycetes) and the genus consists at present of 17 species ( Grice and Dawson, 2017 Theelen et al., 2018). Yeasts of the genus, Malassezia, formerly known as Pityrosporum, are lipophilic yeasts, which are a part of the normal skin flora (microbiome). The aim of this paper is to provide an overview of Malassezia related skin disease, diagnostic methods and treatment options. Skin diseases caused by Malassezia are usually treated with antifungal therapy and if there are associated inflammatory skin mechanisms this is often supplemented by anti-inflammatory therapy. The diagnostic methods used to confirm the presence of Malassezia yeasts include direct microcopy, culture based methods (often a combination of morphological features of the isolate combined with biochemical test), molecular based methods such as Polymerase Chain Reaction techniques, and Matrix Assisted Laser Desorption/Ionization-Time Of Flight mass spectrometry and the chemical imprint method Raman spectroscopy. The species distribution on the skin and the pathogenetic potential of the yeast varies between different Malassezia related diseases such as head and neck dermatitis, seborrheic dermatitis, pityriasis versicolor, and Malassezia folliculitis. The Malassezia yeasts also have a pathogenic potential where they can, under appropriate conditions, invade the stratum corneum and interact with the host immune system, both directly but also through chemical mediators. Malassezia colonize the human skin after birth and must therefore, as commensals, be normally tolerated by the human immune system. Johns Institute of Dermatology, Kings College London, London, United Kingdom 3Department of Skin and Venereal Diseases, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina, Greece.2Department of Clinical Medicine, Health Sciences Faculty, University of Copenhagen, Copenhagen, Denmark.1Department of Dermatology, Zealand University Hospital, Roskilde, Denmark.Saunte 1,2 * †, George Gaitanis 3,4 † ‡ and Roderick James Hay 5 †
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