5. Treatments

Treatment is the same for both verrucas and warts, and is by gradual removal of the hyperkeratotic skin layers and the viral core by keratolytic agents. Active constituents are:

Salicylic acid
In the treatment of warts and verrucas, salicylic acid reduces viral numbers by mechanical removal of infected tissue. It also stimulates production of protective antibodies in response to the mildly irritant effect of the acid. Some products containing salicylic acid, including ointments and collodion-based preparations, are the same as those marketed for corns and calluses.

Lactic acid
Lactic acid is included with salicylic acid in several wart and verruca products. It is corrosive and is claimed to enhance the effects of salicylic acid. Care must be taken that preparations do not spread on to unaffected skin.

Glutaraldehyde
Glutaraldehyde has antiviral activity and a direct anhidrotic effect, drying the verruca and surrounding skin. It stains skin brown, but this fades once treatment is discontinued.

Trichloroacetic acid (TCA)

TCA has a caustic and astringent action that induces the peeling of wart keratotic tissue and the destruction of the causative HPV. 

Silver nitrate
Silver nitrate is a caustic agent. It is used as a stick or pencil (95%, toughened with 5% potassium nitrate) to destroy warts, verrucas and other skin growths. 3–6 daily applications are claimed to be sufficient.

Cryotherapy
Preparations containing dimethyl ether and propane (DMEP) and other liquefied petroleum gases for freezing warts and verrucas are available over the counter.