This observational case series study was done in Department of Dermatology-Baghdad Hospital during January 2008-September 2009. History and examination were done. Koebner¡¯s phenomenon was carried out for all patients on the hidden areas by blunt object, and watched for 1-3 months to observe the appearance of leukoderma.
One hundred thirty-four patients with pityriasis alba were included, their ages ranged from 2 to 15 (7.9 ¡À 3.3) years, family history for vitiligo was positive in 26 (19.4 % ) patients. Nineteen (14.17 % ) patients had coexistence of pityriasis alba and vitiligo lesions and showed positive wood¡¯s light examination for vitiligo, 11 of 19 (57.89 % ) patients had positive family history for vitiligo. Only 32 (23.88 % ) of 134 patients had continued the study and follow-up, 14 (43.75 % ) patients, showed progression of their original pityriasis alba lesion into vitiligo. Also, 11 (34.35 % ) had positive Koebner¡¯s phenomenon and 10 (31.25 % ) patients had positive family of vitiligo.
This study confirmed that pityriasis alba might change into vitiligo by following findings: close association between pityriasis alba and vitiligo, high positive family history of vitiligo among patients with pityriasis alba, high percentage of pityriasis alba progressed to vitiligo and Koebner¡¯s phenomena had a high frequency among patients with pityriasis alba.