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| Fig. 18.3 A, Multiple hypopigmented macules and patches on the torso of a woman with tinea versicolor. B, Enlargement of area in A outlined by rectangle. |
Tinea (pityriasis) versicolor is caused by overgrowth of the normal skin flora of several species of yeast in the genus
Malassezia (Pityrosporum) including
M. globosa, M. sympodialis, M. furfur, M. obtusa, and M. slooffiae. In its pathogenic hyphal form, Malassezia secretes an enzyme that breaks down epidermal unsaturated fatty acids to azelaic acid, which inhibits melanocyte tyrosinase. Tinea versicolor is common in tropical and temperate climates and is found in all races and age groups. The typical lesion is a scaly, slightly erythematous macule or patch located on the proximal anterior and posterior torso (Fig. 18-3). Tinea versicolor may be either hypopigmented or hyperpigmented.
Prohic A, Ozegovic L: Malassezia species isolated from lesional and non-lesional skin in patients with pityriasis versicolor, Mycoses 50:58–63, 2007.
