[2] Risk factors include use of communal showers, having had prior warts, and poor immune function.

[3] This may include salicylic acid, cryotherapy, chemo-based fluorouracil or bleomycin, and surgical removal.

[11][12] Warts may spread through autoinoculation, by infecting nearby skin, or by contaminated walking surfaces.

[citation needed] Plantar warts are often similar to calluses or corns, but can be differentiated by close observation of skin striations.

[citation needed] HPV is spread by direct and indirect contact from an infected host.

A 12-week daily treatment with salicylic acid has been shown to lead to a complete clearance of warts in 10–15% of the cases.

[17] Fluorouracil cream, a chemotherapy agent sometimes used to treat skin cancer, can be used on particularly resistant warts, by blocking viral DNA and RNA production and repair.

[4] Bleomycin, a more potent chemotherapy drug, can be injected into deep warts, destroying the viral DNA or RNA.

Possible side effects include necrosis of the digits, nail loss, and Raynaud syndrome.

[20] Liquid nitrogen and similar cryosurgery methods are common surgical treatments, which act by freezing the external cell structure of the warts, destroying the live tissue.

[citation needed] Laser surgery is generally a last resort treatment, as it is expensive and painful, but may be necessary for large, hard-to-cure warts.

As a short-term treatment, cauterization of the base with anesthetic can be effective, but this method risks scarring or keloids.