Epidemiological survey of skin diseases in schoolchildren living in the Purus Valley (Acre State, Amazonia, Brazil).

A total of 9,955 schoolchildren aged 6-16 years have been examined in a tropical region. The prevalence of dermatosis varied from 21 to 87% in the municipalities surveyed. The most common dermatoses were pediculosis (prevalence 50%), nevi (16.8%), pityriasis versicolor (13.2%), pyoderma (12.2%), pityriasis alba (9.9%), dermatophytosis (6.2%), viral dermatosis (6.2%), scabies (3.0%) and acne vulgaris (2.7%). The prevalence of angular stomatitis, miliaria rubra, candidiasis, piedra nigra, keratosis pilaris, ephelides and geographic tongue is lower but still relatively high. Females had higher rates of pediculosis capitis and males higher prevalence of pityriasis alba. The prevalence of pityriasis versicolor, pigmented nevus and scabies was similar in males and females. Folliculitis, macular pigmented nevi and especially pityriasis versicolor tended to increase with age. Leprosy is hyperendemic in the surveyed area and its rate in the schoolchildren examined was 0.08%. Population movement (urbanization), socioeconomic situation, living conditions, promiscuity, and lack of hygiene may be the cause of such high prevalence and of association of two or more skin conditions. Climatic conditions might have enhanced the prevalence of certain dermatoses (pityriasis versicolor, dermatophytosis, piedra nigra, candidiasis, miliaria rubra).