Summary Background Anecdotal reports suggest that certain disorders are common in African hair and may be associated with hairstyles. Objectives A cross-sectional study of 1042 schoolchildren was performed to test this hypothesis. Methods A questionnaire was administered and scalp examinations performed, after ethics approval. Results Participants included 45% boys and 55% girls. The majority of boys, 72·8%, kept natural hair with frequent haircuts (within 4 weeks). The prevalence of acne (folliculitis) keloidalis nuchae (AKN) was 0·67% in the whole group and highest (4·7%) in boys in the final year of high school, all of whom had frequent haircuts. The majority of girls (78·4%) had chemically relaxed hair, which was usually combed back or tied in ponytails, vs. 8·6% of boys. Traction alopecia (TA) was significantly more common with relaxed than natural hair, with an overall prevalence of 9·4% (98 of 1042) and of 17·1% in girls, in whom it increased with age from 8·6% in the first year of school to 21·7% in the last year of high school. The proportion with TA in participants with a history of braids on natural hair was lower (22·9%), but not significantly, than among those with a history of braids on relaxed hair (32·1%). No cases of central centrifugal cicatricial alopecia were identified. Conclusions We found associations between hairstyle and disease in our population of schoolchildren. AKN appears to be associated with frequently cut natural hair and TA with relaxed hair. These associations need further study for purposes of disease prevention.