By Gary M. White, MD
Pink and hypopigmented, slightly scaly lesions on the back.
Tinea (pityriasis) versicolor is a superficial infection of the stratum corneum by the lipophilic fungus known as Malassezia furfur (formerly pityrosporum). The most common predisposing factor is excessive sweating but others include application of oils and systemic steroids.
The trunk is affected with brown, white, or pink, slightly scaly patches and very thin plaques. If no scale is appreciated, gentle scraping easily generates fine scale. Rarely, TV can affect other locations including the groin, sides of the neck and face. Atrophic lesions may occur [Indian J Dermatol Venereol Leprol 2013;79:270 and JAAD 2017;76;730]. Folliculocentric TV has been reported.
Malassezia fluoresces yellow-green with black (Wood's) light. In a study of 28 patients, 23 (82%) fluoresced positive with Wood's light [Practical Deramtology 2016;March;31]. Positive KOH is the gold standard for diagnosis, but Wood's light is a rapid and inexpensive confirmatory tool.
It is very important to tell patients that the treatment will kill the fungus within days, but any color change will take weeks to months to return to normal. With regard to topical therapy, ketaconazole is the most studied and seemingly the most effective. Clotrimazole cream applied 2/day for 10 days is an alternative. Topical terbinafine is of lower efficacy. If it is to be used, it should be applied 2/day. Of the over-the-counter shampoos, zinc pyrithione seems to be the most effective.
With regard to oral anti fungal agents, itraconazole and fluconazole seem equally effective for the treatment of TV. For simplicity, fluconazole 300 mg po once and repeat in one week is recommended.
Recurrences are common so patients must use some sort of maintenance therapy for years, e.g., until their skin is less oily. This may be in the form of weekly ketoconazole 2% shampoo or topical clotrimazole cream.
Atrophic TV. Indian J Dermatol Venereol Leprol 2013;79:270
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