Pityrosporum yeasts--what's new?

Area of Science:

• Dermatology and Mycology
• Human Cutaneous Microbiome Studies
• Immunodermatology

Background:

• Pityrosporum ovale (P. ovale) is a lipophilic yeast part of normal adult skin flora.
• It is implicated in several skin diseases, including pityriasis versicolor, pityrosporum folliculitis, seborrheic dermatitis, and atopic dermatitis.
• The yeast's morphology can shift from blastospore to mycelial forms, particularly in pityriasis versicolor.

Purpose of the Study:

• To review the role of Pityrosporum ovale in common human skin diseases.
• To summarize current understanding of P. ovale's association with pityriasis versicolor, folliculitis, seborrheic dermatitis, and atopic dermatitis.
• To highlight the therapeutic implications of targeting P. ovale in these conditions.

Main Methods:

• Literature review of studies investigating Pityrosporum ovale and associated skin conditions.
• Analysis of clinical observations and treatment outcomes for pityriasis versicolor and pityrosporum folliculitis.
• Summary of immunological findings in seborrheic dermatitis and atopic dermatitis patients related to P. ovale.

Main Results:

• Pityrosporum folliculitis responds well to antifungal therapy.
• Seborrheic dermatitis patients show altered immune responses to P. ovale, including changes in T-cells and cytokine production (decreased IL-2, IFN-gamma; increased IL-10).
• Atopic dermatitis patients often exhibit positive prick tests to P. ovale extracts, with associated increases in IL-4, IL-10, and IgE.

Conclusions:

• Pityrosporum ovale plays a significant role in the pathogenesis of pityriasis versicolor, pityrosporum folliculitis, seborrheic dermatitis, and atopic dermatitis.
• Antifungal treatment is crucial for managing pityrosporum folliculitis and shows potential benefit in seborrheic and atopic dermatitis.
• Understanding the immune interactions with P. ovale is key to developing effective prophylactic and therapeutic strategies for these skin conditions.