Malassezia (formerly known as Pityrosporum) is a genus of fungi. Malassezia is naturally found on the skin surfaces of many animals, including humans. In occasional opportunistic infections, some species can cause hypopigmentation or hyperpigmentation on the trunk and other locations in humans.
Malassezia species are causing most skin disease in humans, including the most common cause of dandruff and seborrhoeic dermatitis, is M. globosa (though M. restricta is also involved). The skin rash of tinea versicolor (pityriasis versicolor) is also due to infection by this fungus. As the fungus requires fat to grow, it is most common in areas with many sebaceous glands: on the scalp, face, and upper part of the body. When the fungus grows too rapidly, the natural renewal of cells is disturbed, and dandruff appears with itching (a similar process may also occur with other fungi or bacteria).
The fungus appears to play a role in the development of some pancreatic cancers, as a result of it migrating from the gut lumen to the pancreas.