Large, reddish tan, asymptomatic patches recently developed
on the trunk of a 36-year-old man. Five years earlier,
a similar outbreak had resolved after a 10-day course of
oral ketoconazole; this episode was the first recurrence.
Tinea versicolor is a superficial skin infection caused
by Pityrosporum orbiculare and Pityrosporum ovale, also
known as Malassezia furfur. The diagnosis is easily made
by the clinical appearance and can be confirmed by a potassium
hydroxide preparation that shows hyphae--short,
rod-shaped fragments intermixed with round spores and
grapelike clusters--in what is referred to as the "spaghetti
and meatballs" pattern. Recurrences are common and
occur most often in the spring and summer.
Topical treatments include selenium sulfide suspension
2.5%, sodium thiosulfate 25%, ketoconazole, miconazole,
clotrimazole, econazole, ciclopirox, sulfosalicylic
acid shampoo, and zinc pyrithione shampoo. Oral therapies
include ketoconazole, itraconazole, and fluconazole.
Griseofulvin is ineffective.
A 10-day course of oral ketoconazole was prescribed
because of its previous effectiveness in this patient.
(Case and photographs courtesy of Dr Robert P. Blereau.)