To assess clinical findings associated with Wuchereria bancrofti infection, 192 school children in a filariasis-endemic area of Haiti underwent physical and ultrasonographic examinations and testing for circulating filarial antigen (CFA). The CFA-positive children were more likely than CFA-negative children to have severe interdigital lesions (> or = 1 macerated lesion with involvement of > or = 4 toe web spaces) (P < 0.0001) and inguinal (P = 0.003) or crural (P = 0.004) lymph node pathology. In multivariate analysis, CFA positivity remained a significant predictor for severe interdigital lesions (P = 0.006) and inguinal lymph node pathology (P = 0.05). Ultrasound detected adult worms and lymphangectasia (diameter = 2.0-4.0 mm) in 11 (10.8%) CFA-positive children. Among CFA-positive children, ultrasonographic detection of adult worms was associated with inguinal (P = 0.01) and crural (P = 0.004) lymph node pathology and advanced pubertal stage (sexual maturity rating = 3-5) (P = 0.02). This is the first study to associate interdigital lesions with filarial infection in children.