Pityriasis Alba

General Information
Pityriasis alba (PA) is a common skin disorder affecting children between the ages of 6-12. Dry round scaly patches appear most often on the face, but can also involve the upper arms, neck or shoulders. The duration can vary between a couple of months to a couple of years, the lesions eventually subside and the affected area will repigment. Medical therapy is not always necessary. PA is asymptomatic with resolution occurring on its own. Healthcare providers may prescribe emollients, topical steroids and psoralen plus ultraviolet light A photochemotherapy (PUVA) may be used to help with repigmentation in extensive cases, although the recurrence rate is high after treatment is stopped.

Epidemiology
Relatively common, around 5% of children in the United States

Etiology
Unknown, common factors include dry skin

Pathogenesis
Pruritic lesions evolve to scaly and hypopigmented lesions

Clinical
Lesions appearing hypopigmented, round and scaling. Varying in 1-4 cm in diameters

Histology
Lymphocytes are present more at the junction of dermis and epidermis than in the basal layer itself, the stratum corneum is normal, devoid of even a hint of parakeratosis.

Bibliography
1. “Pityriasis Alba” (Online). May 2006. http://www.emedicine.com/emerg/topic425.htm (visited: April 1, 2008) 2. “Pityriasis Alba” (Online). November 2007. http://www.emedicine.com/ped/TOPIC1813.HTM (visited: April 1, 2008)

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 Pityriasis Alba