Topical salicylic acid solutions, gels, and plasters (ranging from 17 % to 40 %, available over the counter)

Paring—Using a 15-blade in the office, warts can be pared or shaved to the level of the lower epidermis (visualization of “bleeding points” or dermal capillaries is an endpoint). This allows for better penetration of medication or cryotherapy. At home, patients can be instructed to self-pare using a nail file or dull blade.

Liquid nitrogen application/cryotherapy—Liquid nitrogen is inexpensive, quick to apply, effective, and cold (−321 °F). Typically it requires several sessions spaced apart by 2–4 weeks for maximum efficacy, and each session may include two to three cycles of application with a 10 s thaw time per cycle.

Electrocautery—Using an electrodesiccator device, warts can be cauterized and removed. One should ideally take care to use a smoke evacuator system, to minimize both patient and practitioner exposure to aerosolized HPV particles in the generated smoke plume.

5-fluorouracil—This topical chemotherapeutic cream has virucidal properties and is available by prescription. It can be combined or alternated with salicylic acid to increase epidermal penetration.

Imiquimod—Imiquimod (Aldara™) 5 % cream is an immunomodulator that is Food and Drug Administration (FDA) approved for use for genital and perianal warts in patients 12 years or older. It induces skin cells to secrete interferon alpha and other cytokines. It can also be used off-label for non-genital warts, with less reliable efficacy.

Cantharidin/ podophyllin resin—Office-applied compounds secreted by the blister beetle and American May Apple tree, respectively, they cause blistering and necrosis of involved skin. Several treatments may be required.

Podophyllotoxin—This is a cytotoxic compound that tends to work better on mucosal surfaces and is used more commonly in the treatment of genital warts. Patients may apply it topically twice daily for 3 consecutive days per week and repeated weekly, not to exceed 4 weeks.

Sinecatechins—Veregen™ 15 % ointment is a water extract of green tea leaves from Camellia sinensis. It has been shown to inhibit enzymes related to viral replication, and is approved for use on genital warts.

TCA—Trichloroacetic acid is another means of physical destruction, via chemical coagulation of proteins.

Intralesional interferon, candida antigen, or bleomycin—The first two are considered forms of intralesional immunotherapy, whereas bleomycin is directly cytotoxic.

Oral cimetidine—At high doses, this type-2 histamine receptor antagonist displays immunomodulatory properties and may therefore treat warts; however, efficacy is variable. Dosing in adults and children is 20–40 mg/kg orally per day in divided doses every 6 h, not to exceed 2,400 mg/day in adults. There are many known drug interactions with cimetidine, so this medication should be used with caution.