Isolated scalp involvement with pityriasis versicolor alba (Pityrias Versicolor Albus Capitis) in a patient from a dry temperate region
Published Web Locationhttps://doi.org/10.5070/D30qx2p4qz
Isolated scalp involvement with pityriasis versicolor alba (pityrias versicolor albus capitis) in a patient from a dry, temperate
From the Dermatology Department, Shiraz University of Medical Sciences, Shiraz, Iran. email@example.com
M Naseri MD and MR Namazi MD
Dermatology Online Journal 9(3): 17
Pityriasis versicolor (tinea versicolor) is a common superficial fungal infection of the skin involving the hyphal (filamentous) form of Pityrosporum orbiculare. Clinical cutaneous infection is common in humid, tropical climates, but declines to less than 5 percent in temperate climates. Isolated face or scalp involvement is rare. We present a boy living in a temperate region who had sudden onset of scalp and hairline involvement with tinea versicolor.
|Whitish discoloration of the skin near the hair margin due to pityriasis versicolor alba.|
A 12-year-old boy with skin type IV who was living in a village with a dry, temperate climate was referred to our center for evaluation of asymptomatic skin discoloration present for 4 days. Skin examination revealed the presence of patchy and confluent areas of macular hypopigmentation, with scant scale, along the hair margin of the forehead and temple areas (Fig. 1). With Wood's lamp examination, the above areas as well as the whole scalp showed a pale-yellow fluorescence. A KOH preparation revealed the presence of hyphae and spores in a spaghetti-and-meatballs pattern. The patient's problem was diagnosed as pityriasis versicolor alba.
Pityriasis versicolor (tinea versicolor) is a common, chronic, superficial fungal infection of the skin due to the hyphal (filamentous) form of Malassezia furfur (synonym Pityrosporum orbiculare). Its incidence reaches 50 percent in humid, tropical climates, and declines to less than 5 percent in temperate climates.  The infection tends to flare during warm weather.  The color of the lesions varies from almost white to reddish-brown or fawn-colored. 
In dark-complexioned children, a severe, rapidly spreading, hypopigmented variant may occur, colorfully called pityriasis versicolor alba or achromia parasitica.  The cause of hypopigmentation is unclear. Ultrastructural studies have shown that affected skin has an abnormality of melanosome number and packaging, with hypopigmented areas demonstrating a decreased number of individually dispersed melanosomes.  Extracts of Malassezia furfur cultures contain C9-C11 dicarboxylic acids that may inhibit tyrosinase. 
The site most commonly affected by pityriasis versicolor is the upper trunk. Other parts of the body such as axillae, groins, and genitalia may also be involved. Isolated facial and scalp involvement, as occurred in our case, is rare and mainly occurs in tropical locations.
Isolated involvement of body areas with pityriasis versicolor alba may be misdiagnosed as vitiligo, especially when the lesions have only slight scale, which may not be noticed by the inexperienced physician. However, in tinea versicolor alba the history is usually of short duration and scale can usually be appreciated when the affected skin is stretched or firmly scraped. In addition, Wood's lamp examination shows yellowish fluorescence only in pityriasis versicolor.
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