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The human papillomavirus (HPV) causes anogenital warts (condylomata acuminata) in adults and children. Anogenital warts were once a rare pediatric infection with only 34 cases reported prior to 1982. The increasing number of infected children parallels the explosive epidemic of adult HPV disease that began in the mid-1960s.1
The medical evaluation and management of HPV infection in children is complicated by a long viral latency period, several possible modes of transmission including sexual transmission, and no single effective treatment regimen. Human papillomavirus also is associated with cervical, anal, and penile carcinomas in adults. Affected children are at potential risk for the development of such cancers. This article reviews the basic molecular biology of HPV, its major manifestations, evaluation, and treatment of infections in children.
BACKGROUND
The human papillomavirus is a nonenveloped, icosahedral, double-stranded deoxyribonucleic acid (DNA) virus of the family Papovaviridae. With the advent of recombinant DNA technology in the mid-1970s and the cloning and sequencing of HPV DNA, multiple types of HPV were identified.2 A new virus isolate is considered to be a distinct type if it contains less than 50% homology with known viral types. Approximately 70 viral types have been described.3 The association of different HPV types with specific sites of infection is now well known. Types 1 and 4 are associated with plantar warts, with type 2 isolated from common warts. Types 6 and 11 are found most often in grossly apparent genital condyloma acuminata, laryngeal papillomas, and conjunctival infections. Types 16, 18, 31, 33, and 35 also infect the genital tract as cervical flat warts and cervical atypia. These are the types that not only can cause anogenital cancers but also have been reported in squamous cell carcinomas of the respiratory tract and at other cutaneous sites.4·5 Several types are associated with a rare, autosomal recessive dermatologie condition, epidermodysplasia verruciformis, in which affected individuals demónstrate a strong tendency to develop multiple wart-like lesions caused by HPV.6
HISTOPATHOLOGY
Human papillomavirus is an epitheliotrophic virus. It attacks the nucleus of squamous epithelial cells, entering at the basal layer of the epidermis presumably at sites of microtrauma. The result is hyperplasia of basal and parabasal cells (acanthosis), degenerative cytoplasmic vacuolization (koilocytosis), and variable thickening of the more superficial epidermal layers (hyperkeratosis and parakeratosis)....