Malassezia folliculitis or pityrosporum folliculitis,
is a skin condition caused by infection by ''
Malassezia
''Malassezia'' is a genus of fungi (specifically, a yeast belonging to the division Basidiomycota).
Some species of ''Malassezia'' are found on the skin of animals, including humans. Because malassezia requires fat to grow, it is most common in ...
'' (formerly ''Pityrosporum'')
yeast
Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom (biology), kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are est ...
.
The skin of the upper trunk area including the back, chest, arms and sometimes the neck is often affected and this condition is often seen in young to middle aged adults, although it has been known to occur in adults well into their sixties, and can also be found on the lower extremities as well. Its diagnosis is based on the pruritic (itchy) papulopustules found in a follicular pattern in these regions.
Pustules are caused by an overgrowth of the yeast ''
Malassezia furfur
''Malassezia furfur'' (formerly known as ''Pityrosporum ovale'') is a species of yeast (a type of fungus) that is naturally found on the skin surfaces of humans and some other mammals. It is associated with a variety of dermatological conditions ...
'' (formerly ''Pityrosporum ovale''), which plugs the follicles. This yeast is
lipophilic
Lipophilicity (from Greek language, Greek λίπος "fat" and :wikt:φίλος, φίλος "friendly") is the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. Such compounds are c ...
, requiring fatty acids that are present in oily skin to proliferate. It has been shown that ''
Malassezia
''Malassezia'' is a genus of fungi (specifically, a yeast belonging to the division Basidiomycota).
Some species of ''Malassezia'' are found on the skin of animals, including humans. Because malassezia requires fat to grow, it is most common in ...
'' yeast grows by consuming
fatty acid
In chemistry, in particular in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated and unsaturated compounds#Organic chemistry, saturated or unsaturated. Most naturally occurring fatty acids have an ...
s with
carbon chain
In chemistry, catenation is the bonding of atoms of the same element into a series, called a ''chain''. A chain or a ring may be ''open'' if its ends are not bonded to each other (an open-chain compound), or ''closed'' if they are bonded in a ...
lengths C11 to C24.
Malassezia is part of the normal skin flora, but overgrows in certain conditions.
Overgrowth is associated with oily skin, humidity or other pre-existing dermatologic conditions such as seborrheic dermatitis and severe dandruff.
See also
*
Skin lesion
A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of this ...
*
List of cutaneous conditions
Many skin conditions affect the human integumentary system—the organ system covering the entire surface of the Human body, body and composed of Human skin, skin, hair, Nail (anatomy), nails, and related muscle and glands. The major function o ...
References
{{Mycoses
Mycosis-related cutaneous conditions