High prevalence of non-leprotic hypochromic patches among children in a rural area of Mali, West Africa.

The identification of one or several hypochromic patches (HP) on the skin is a key stage in the diagnosis of leprosy on dark skin. However, HP are often caused by other disorder than leprosy. A study to determine the prevalence and causes of HP among children was carried out in a rural area of Mali in November 2001. All children under 15 years of age in two villages in an endemic area were screened by two dermatologists. Among the 1729 children seen, HP were identified in 71 patients, with a prevalence of 4.1%. The most common cause of HP was tinea versicolor, which was present in 39.4% of children with HP, followed by pityriasis alba in 31%, naevus achromicus in 24% and vitiligo in 5.6%. No case of leprosy was detected. Our study raises several points with practical consequences for the detection of leprosy cases: the high prevalence of non-leprous HP compared to leprosy, the reliability of the clinical diagnosis of leprosy, and the role of general health care workers in the detection of leprosy cases. Helping those who should be involved in that detection in distinguishing true cases from other hypochromic disorders appears to be a priority.