A wart is the common name for what are generally known as common warts. Common warts are caused by a human papillomavirus infection and are contagious, but are not immediately contagious on contact. Common warts are benign tumors caused by human papillomavirus infection of the skin and mucous membranes. The disease is mainly transmitted through tiny injuries to the skin and mucous membranes, and replicates and proliferates within the epithelial cells, leading to abnormal differentiation and proliferation of the epithelial cells and the production of benign epithelial superfluous organisms. Common warts can occur anywhere on the body, but are more common on the hands. Soybean-sized or larger grayish-brown, tan, or skin-colored papules with a rough, hard surface may be papillomatous proliferations. Common warts are most common in immunocompromised people and are caused mainly by direct or indirect contact. So common warts can be transmitted to others.