Warts are common skin growths caused by the human papillomavirus (HPV). It has been estimated that up to 1 in 20 school age children will have warts. Common warts usually affect the hands of children or adults with significant water exposure at work. Plantar warts occur on the soles of the feet and may be annoyingly painful with walking. Flat warts tend to be very small and appear in large numbers. They can appear on the face of children but are also seen on the beard area of men and legs of women due to shaving. Warts are contagious and spread from one person to another with skin contact.