Pityriasis versicolor

Abstract

Pityriasis versicolor (PV) is one of the most common infectious skin diseases, as well as the most common dermatosis associated with pigmentation alterations of the skin. PV is prevalent in 1% of the population living in temperate climate zones and more common during the summer. In tropical areas, PV is found in up to 50% of all patients consulting a dermatologist. Of the known Malassezia species, M. globosa is currently felt to play a key role in the pathogenesis of PV, as it is most commonly found in PV lesions. In addition, its round-shaped cells may contribute to the characteristic histology of the disease ("spaghetti and meatballs"). However, the clinical appearance of PV including hyper- and hypopigmentation, fluorescence of the lesions, as well as a lack of inflammation despite high fungal load cannot fully be explained by the presence of M. globosa, which is also found on healthy skin. In M. furfur a tryptophan-dependent metabolic pathway generates a number of indole pigments, which may be associated with the clinical appearance of PV. In the model organism Ustilago maydis it was shown that the formation of the indole compounds occurs spontaneously after initial conversion of tryptophan into indole pyruvate controlled by the key enzyme aminotransferase Tam 1. We review the present knowledge of PV and highlight the potential role of Tam1 in explaining the poorly understood aspects of the disease. Promising therapeutic results using the application of Tam1 inhibitors to treat PV support the enzyme's important role in the disease pathogenesis.

Characterization of tryptophan aminotransferase 1 of Malassezia furfur, the key enzyme in the production of indolic compounds by M. furfur

“…Malassezia yeasts are part of the resident skin flora. However, additional – so far unidentified – factors than just occurrence of the fungi are necessary to induce PV . So far, it was not possible to induce pigment production for M. globosa in vitro ; however, M. furfur produces pigments when tryptophan is present in the culture .…”

“…Pityriasis versicolor (PV), a common skin disease associated with hyper‐ or hypopigmentation, is caused by fungi of the genus Malassezia . Of the 14 identified Malassezia species , Malassezia globosa is supposed to play a key role in the pathogenesis of PV .…”

“…Of the 14 identified Malassezia species , Malassezia globosa is supposed to play a key role in the pathogenesis of PV . However, PV characteristics such as pigmentation alterations, fluorescence of PV lesions or minimal signs of inflammation despite high fungal load cannot be explained just by occurrence of M. globosa . Instead, it was shown that with tryptophan as a nitrogen source, Malassezia furfur produces a number of indole pigments and alkaloids, which are related to the clinical appearance of PV .…”

“…Currently, antimycotics such as azoles are used for the treatment of PV. More specific inhibitors, such as MfTam1 inhibitors, would protect the skin flora, reduce the risk of resistances and would be especially applicable for prophylaxis of the recurrent episodes . Furthermore, availability of the recombinant enzyme allows detailed investigations of its role in the pathogenesis of PV.…”

The Beneficial Effects of Extract of Pinus densiflora Needles on Skin Health

“…Common skin diseases associated with inflammation such as pityriasis versicolor are caused by a fungus of the genus Malassezia [12,25]. Among the Malassezia species, Malassezia furfur is associated with pityriasis versicolor [15], folliculitis [1], seborrheic dermatitis [2], atopic dermatitis [38], and psoriasis [31].…”