[Pityriasis versicolor due to Malassezia ovalis]

Area of Science:

• Dermatology
• Mycology
• Infectious Diseases

Background:

• Pityriasis versicolor is a superficial fungal infection affecting the skin.
• The condition is caused by yeasts of the Malassezia genus.
• Previous studies have suggested variations in the morphology and clinical presentation of pityriasis versicolor.

Purpose of the Study:

• To investigate the prevalence and characteristics of different fungal forms in pityriasis versicolor.
• To compare the clinical presentation and patient demographics associated with ovoid (Malassezia ovalis) and globous (Malassezia furfur) fungal units.

Main Methods:

• A study of 175 patients with pityriasis versicolor in Venezuela.
• Microscopic examination of skin scales to identify fungal morphology (ovoid vs. globous).
• Analysis of patient age, sex, lesion distribution, and age of onset.

Main Results:

• 87% of patients were infected with globous Malassezia furfur, and 13% with ovoid Malassezia ovalis.
• Malassezia furfur patients were younger (median age 24.5 years) with lesions appearing earlier (median age 20 years).
• Malassezia ovalis patients were older (median age 37.5 years) with lesions appearing later (median age 31 years).
• Lesion distribution differed: M. ovalis on the lower trunk and limbs, M. furfur on the chest, neck, face, and upper limbs.

Conclusions:

• Two distinct clinical presentations of pityriasis versicolor may be associated with different Malassezia morphologies.
• The ovoid form (M. ovalis) may favor less-sweating areas and older individuals, while the globous form (M. furfur) is more common in younger individuals.
• Further research is needed to confirm the distinct roles of M. ovalis and M. furfur in pityriasis versicolor pathogenesis.