Epidemiologic data are essential to understand implications of human diseases. Studying incidence and prevalence of specific diseases are fundamental in decision-making regarding allocating resources for clinical care. 1 If the goal is to understand and prevent disease causes in populations, then population-based epidemiologic studies are the gold standard to address major determinants of health and disease at this level and yield most accurate data. 2 Epidemiology is inevitably entangled with society, and it is not desirable to study the causes of disease in the abstract. 3 Epidemiology has contributed to better understanding of etiology, therapy, and/or prevention of skin diseases as detecting the association between psoriasis and cardiovascular disease, 4 identifying drugs associated with severe cutaneous drug eruptions, 5 and the association between UV exposure and melanoma, 6 but unfortunately, this type of studies is relatively lacking. 1The skin is not just an inactive covering of the body but a delicate active boundary and a vital organ of social contact 7 and performing epidemiological studies is very crucial to determine extent of skin diseases as a public health and to direct proper medical care. 8 Cutaneous hypopigmentations enclose a wide range of disorder, 9 which affect 4% of children 10 and represent third most common reason for patients with richly pigmented skin seeking dermatological treatment. 11 Most common causes of hypopigmentation especially in children include pityriasis alba (P. alba), pityriasis versicolor

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