Pityriasis versicolor alba

Abstract

Pityriasis versicolor alba is a hypopigmented or depigmented variant of pityriasis versicolor characterized by maculous, partly pityriasiform, scaly depigmented lesions occurring particularly in seborrhoeic areas. Long-persisting hypopigmentation after healing of the pityriasis versicolor was first described by Gudden in 1853. Hypopigmentation and depigmentation were later differentiated as an independent variant of the disease. In 1848, Eichstedt recognized the pathogen-related character of pityriasis versicolor in its hyperpigmented form. Today it is generally accepted that the disease is caused by yeasts of the genus Malassezia, of which nine species are differentiated. It is controversial whether a single species is responsible for the disease. The pathogenesis of depigmentation has not been established. A screening effect by the scale layer as well as toxic effects on pigment synthesis by fungal metabolites have been discussed. With regard to the second mechanism, the newly discovered tryptophan-derived metabolites of M. furfur might be significant. Evidence-based data concerning the therapy of pityriasis versicolor alba do not exist. According to current recommendations, pityriasis versicolor should be rapidly treated with antimycotics, followed by ultraviolet therapy to induce maturation of existent melanosomes and accelerate repigmentation. However, depigmented lesions are difficult to improve by ultraviolet therapy.

Malassezin, a Novel Agonist of the Aryl Hydrocarbon Receptor from the Yeast Malassezia furfur, Induces Apoptosis in Primary Human Melanocytes

“…At present, either a selective toxic influence on the skin's pigmentary system, namely on melanocytes, or an inhibition of tyrosinase by metabolites of the yeast, such as azelaic acid, are considered possible causes. [12,15] Reports of histopathological light and electron microscopic examinations have been somewhat controversial and demonstrated signs of selective toxic degeneration of melanocytes in affected areas and a disturbed distribution of melanosomes. We now describe, for the first time, a toxic influence of the Malassezia indoles on cultured melanocytes.…”

“…Histopathological and ultrastructural examinations of the lesions have led to somewhat contradictory findings, such as decreased numbers of melanosomes [8] and melanocytes, [9] disturbed transport of melanosomes to keratinocytes, [10] and morphological changes in melanocytes that were ascribed to toxic influences. [11,12] This prompted us to investigate the influence of Malassezia alkaloids on cultured primary human melanocytes.…”

Aspectos clínicos de pacientes com pitiríase versicolor atendidos em um centro de referência em dermatologia tropical na cidade de Manaus (AM), Brasil

“…21 Thoma described a variant called "Alba" for pityriasis versicolor. 22 An erythematous macular variant (pityriasis versicolor rubra) and another with black lesions (pityriasis versicolor nigra) were described, as well as their transformation from one form to the other or even to the hypochromic or alba variant. 23 DiFonzo and Faggi mention the association of two colors in the same individual.…”

Hypopigmenting agents: an updated review on biological, chemical and clinical aspects

“…Melatonin receptor activation has been suggested as a peculiar biological mechanism to cause toxic melanin synthesis intermediate release and its possible involvement in vitiligo (Slominski et al, 1989). Some fungal metabolites of dermatophytes, Malessezia yeasts and lichen were found toxic to melanocytes explaining depigmented lesions on the skin (Carlson et al, 2002;De Luca et al, 1996;Podobinska et al, 2003;Thoma et al, 2005).…”