Crude lipid material elaborated and excreted by the organism Pityrosporum ovale, the lipid obtained by chloroform extraction of the washed organisms, and various fractions of this chloroform-extractable material have all been shown to provoke the appearance of follicular acanthosis and intrafollicular keratin accumulation of the sebaceous follicles when inuncted on the skin of the external ear canal of albino rabbits. The most active fractions contain titratable acidity and chromatographic evidence of free fatty acids. This organism has also been shown to be capable of utilizing several triglycerides as substrates and in the process, to release fatty acids into the medium. These observations raise the possibility that P ovale may likewise contribute to the formation of comedones in the sebaceous follicles of man. Additional observations are needed to clarify the human comedogenic potential of this neglected organism.
Weary PE. Comedogenic Potential of the Lipid Extract of Pityrosporum ovale. Arch Dermatol. 1970;102(1):84-91. doi:10.1001/archderm.1970.04000070086013