Objective: To identify the types of human papillomaviruses found in anogenital warts in children and to relate these to clinical and social information. Design: In situ hybridisation using biotin labelled DNA probes to 11 types of human papillomavirus was performed on biopsy specimens from 17 children with anogenital warts. Setting: Nuffield department of pathology and the department of dermatology, Oxford. Patients: Children in one group were referred by general practitioners or paediatricians to the dermatology department, where biopsies were performed. The other children were seen in four different hospitals, and biopsy specimens were submitted to the laboratory at the physician's or pathologist's request. Results: Of the 17 biopsy specimens, 10 contained cells positive with a probe to a genital human papillomavirus type (types 6 or 11), while six were positive with a skin virus type (type 2 or 3). One was negative. The virus type present bore no relation to the site or appearance of the warts. The virus type did, however, appear to correlate with groups of children. Skin types were commoner in older children (over 4 years), in those with a relative who had skin warts, and in children with warts elsewhere; there was no relation with the child's sex and no suspicion of sexual abuse in these children. These circumstances suggested non-sexual transmission, such as autoinoculation. In contrast, genital types were commoner in girls, in children under 3 years, in children with relatives with genital warts, and in those with no warts elsewhere. Nevertheless, there was suspicion or evidence of sexual abuse in only half these children, suggesting that other routes of transmission - for example, perinatal - might have been implicated. Conclusion: Anogenital warts in children may contain either skin or genital wart virus type. Although the type of human papillomavirus present may give some indication of the likely mode of transmission, this can be interpreted only in conjunction with all available clinical and social information. The type of virus does not provide proof of the presence or absence of sexual transmission.
