Varied Presentations of Tinea Versicolor: Tinea Versicolor Confined to One Site

For several months, a 19-year-old man had asymptomatic hyperpigmented and hypopigmented macules on the right volar forearm. Recent applications of topical corticosteroids made the lesions more noticeable.

Many of the round patches featured fine scales. Examination of a potassium hydroxide( (KOH) preparation of material from a scaly lesion revealed the typical “spaghetti and meatballs” appearance of hyphae and budding yeast indicative of tinea versicolor. This infection is caused by Malassezia furfur, a lipophilic commensal yeast that is part of the normal flora in the keratin layer of all humans. Overgrowth, which leads to visible lesions, is more likely in humid environments, in susceptible persons who use topical corticosteroids, and in those who produce excessive sebum.

The incidence of tinea versicolor is higher in regions close to the equator. The single site of eruption with no signs of involvement elsewhere on this patient was atypical. However, the characteristic KOH findings ruled out other conditions in the differential diagnosis, such as pityriasis alba, vitiligo, tinea corporis, nummular eczema, seborrheic dermatitis, and guttate psoriasis. For example, the hyphae seen on a KOH preparation of scrapings from tinea corporis are typically much longer, more discrete, and more filamentous than the short, clumped hyphae of tinea versicolor.

(Case courtesy of Joe Monroe, PA-C.)