Common warts, also known as verruca vulgaris, are caused by the human papillomavirus (HPV), most frequently HPV types 1, 2, and 4. Infection is usually at sites prone to frequent trauma such as fingers, hands, knees, and elbows, but common warts can occur on virtually any epidermal surface as well as mucosal surfaces. Warts may be pruritic, and scratching can produce a linear array of lesions via autoinoculation. Widespread, persistent lesions may be a clue to an underlying inherited or acquired immunodeficiency.

Verruca vulgaris lesions are more prevalent in children aged 4-12 years. The HPV virus is often passed between siblings and may be observed as cyclical infections.

Introduction of HPV into the anogenital area in children can be from several modes of transmission. Vertical transmission has been reported to be responsible for at least 20% of lesions. Horizontal transmission by caregivers in the first days of life is another modality of HPV contamination in newborns. There is also heteroinoculation by affected family members with common warts (verruca vulgaris) and autoinoculation from children who have a cutaneous or oral infection. Nevertheless, perianal and genital warts may be a sign of sexual abuse and must be investigated appropriately.