Malassezia is a genus of fungi

Fungus

A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...

. Malassezia is naturally found on the skin surfaces of many animals, including humans. In occasional opportunistic infection

Opportunistic infection

An opportunistic infection is an infection caused by pathogens, particularly opportunistic pathogens—those that take advantage of certain situations—such as bacterial, viral, fungal or protozoan infections that usually do not cause disease in a healthy host, one with a healthy immune system...

s,
some species can cause hypopigmentation

Hypopigmentation

Hypopigmentation is the loss of skin color. It is caused by melanocyte or melanin depletion, or a decrease in the amino acid tyrosine, which is used by melanocytes to make melanin.-Treatments:...

 on the trunk and other locations in humans. Allergy tests for this fungus are available.
Due to progressive changes in their nomenclature, some confusion exists about the naming and classification of Malassezia yeast species.