Common warts. These present as dome-shaped papules or nodules with a papilliferous surface. They are usually multiple, and are commonest on the hands (Fig. 1) or feet in children but also affect the face and genitalia. Their surface interrupts skin lines. Some facial warts are ‘filiform’ with fine digit-like projections.

Plane warts. These are smooth flat-topped papules, often slightly brown in colour, and commonest on the face (Fig. 2) and dorsal aspects of the hands. They are usually multiple and resist treatment, but eventually resolve spontaneously, often after becoming inflamed. They can show the Koebner phenomenon.

Plantar warts. These are seen in children and adolescents on the soles of the feet; pressure causes them to grow into the dermis. They are painful and covered by callus, which, when pared, reveals dark punctate spots (thrombosed capillaries). Mosaic warts are plaques on the soles that comprise multiple individual warts.

Genital warts. In males, these affect the penis and, in homosexuals, the perianal area. In females, the vulva, vagina and perianal area maybe involved (Fig. 3). The warts may be small or may coalesce into large cauliflower-like ‘condylomata acuminata’. Proctoscopy (if perianal warts are present) and colposcopy (for female genital warts) are needed to identify and treat any rectal or cervical warts because of the risk of neoplastic change. Sexual partners need to be examined.