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A young black man presents to the office with a 5-year history of white spots on his trunk (Figure 147-1). He denies any symptoms but worries if this could spread to his girlfriend. These spots get worse during the summer months but never go away completely. He was relieved to receive a treatment for his tinea versicolor and to find out that it is not spread to others through contact.
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Tinea versicolor is a common superficial skin infection caused by the dimorphic lipophilic yeast in the genus Malassezia, formerly known as Pityrosporum. The most typical presentation is a set of hypopigmented macules and patches with fine scale over the trunk and proximal upper extremities in a capelike distribution.1
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Pityriasis (from Pityrosporum) versicolor is actually a more accurate name, as "tinea" implies a dermatophyte infection. Tinea versicolor is caused by yeast in the genus Malassezia and not a dermatophyte.1,2
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Seen more commonly in men than in women.
Seen more commonly in adolescents and young adults.
Seen more often during the summer and is especially common in warm and humid climates.
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ETIOLOGY AND PATHOPHYSIOLOGY
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Tinea versicolor is caused by yeast in the genus Malassezia which is a lipid-dependent, dimorphic fungus that is a component of normal human cutaneous flora.2,3
Malassezia lipophilic yeasts are causative agents in tinea versicolor, seborrheic dermatitis, and Malassezia folliculitis and can even exacerbate atopic dermatitis.2 In one microbiology study using polymerase chain reaction (PCR), the authors were able to determine the prevalence of various Malassezia species on patients with Malassezia associated skin conditions.2 The two most common species isolated from humans were M. globosa and M. furfur.2
Transformation of Malassezia from yeast to the pathogenic mycelial form followed by invasion into the stratum corneum precedes the development of the classic appearance of tinea versicolor.4
Versicolor refers to the variable changes in pigmentation noted in this condition.2-4
Hypopigmentation changes are secondary to melanocytic damage caused by azelaic acid produced by the genus Malassezia, while the hyperpigmented and erythematous lesions are a result of an inflammatory reaction to the organism.4
Malassezia is lipid dependent and thrives on sebum and moisture. The lesions are more common in areas of greater sebum production, such as the upper trunk and proximal upper extremities.2,3
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Tinea versicolor consists of hypopigmented, hyperpigmented, or pink macules ...