Warts are small growths on the skin that are caused by the human papilloma virus (HPV). They generally appear as skin-colored bumps with a raised, rough surface. Although much of the time warts are harmless, and clear spontaneously within 1-2 years,^[1] they may also require medical treatment depending on their location and symptoms.^[2][3] Generally, warts are uncommon in infants, common in children, and decline in prevalence into adulthood.^[4] It is important to note that warts are caused by the HPV virus, not to be confused with genital herpes (which is caused by the herpes simplex virus, HSV), or senile warts (seborrheic keratosis, a benign skin tumor of unknown etiology).

The presence of one or more round, raised, rough surfaces on the skin (usually on the hands or feet) can indicate the presence of warts. Warts can vary in appearance depending on their location on the body and the infecting HPV strain. They may have numerous small black dots on their surface, which are clotted blood vessels.^[2][4] Although warts are often asymptomatic (other than the change in appearance of affected skin), they can have negative effects on quality of life by causing physical discomfort or psychological distress over cosmetic appearance.^[3][4]

Warts are diagnosed by health care providers during a clinical exam; diagnosis is based on their visual appearance.^[5] If there is any doubt about the diagnosis, a skin biopsy may be collected and analyzed to rule out other types of skin growths, such as cancer.^[5] Although PCR genotyping techniques can readily determine the specific HPV type(s) responsible for the infection, the specific infecting HPV strain does not affect the recommended treatment.^[2][6]

For new warts, watchful waiting may be recommended instead of treatment, as many warts resolve on their own.^[7] Otherwise, the main medical treatments for warts are topical medications, which are applied directly to the wart. Salicylic acid is often the first line of treatment, since it can be acquired without a prescription and has a cure rate of 50-70%, although it usually takes several weeks of application to work.^[5] Cryotherapy is another first-line topical treatment, in which liquid nitrogen is applied directly to the wart. In addition to destroying the HPV-infected wart cells, the tissue damage caused by topical therapies stimulates the immune system, which may play a role in the eventual clearing of not only the treated wart, but warts at other sites in the body.^[8][5][9]

The following supplements have been studied for warts:

• Vitamin B-12^[10]
• Folate^[10]
• Ferritin^[10]
• Vitamin D^[10]
• Echinacea^[11]
• Zinc^[12]
• Vitamin A^[13]

Research on the impact of diet on warts is scarce. However, one area in which the effect of diet on the clearance of HPV infections has been studied is in the context of cervical cancer, which is caused by HPV. One observational study found an association between HPV resolution and higher total intake of whole fruits, seafood and plant protein.^[14] While more research is needed, it is reasonable to assume that dietary habits with known positive effects on the immune system, such as high intake of fruits and vegetables,^[15] could help either minimize the risk of getting warts or promote their clearance.

In addition to the common topical treatments for warts, such as salicylic acid or cryotherapy, many other treatments have been used. However, not all of the following have been rigorously tested in randomized controlled trials, so high-quality evidence for their efficacy is currently lacking:^[16]

• Topical agents with antiviral activity such as zinc, imiquimod, 5-fluorouracil, or acyclovir
• Intralesional bleomycin^[17] (i.e., bleomycin injected directly into the wart)
• Candida antigen ^[17]
• Laser removal
• Curettage: warts are scraped off with an instrument
• Burning (electrocautery)
• Covering the wart with duct tape^[18]
• Photodynamic therapy^[4]

Warts are caused by human papilloma virus (HPV). Although there are more than 150 strains of HPV, only a limited number cause warts.^[2][5][19] HPV is spread through skin contact—either from body part to body part in the same individual, or from contact with other infected individuals. HPV can also spread by sharing objects that have come into contact with the virus, such as washcloths, towels, or clothing. Infections typically occur on areas of broken skin, where the skin barrier is compromised. Whether or not a wart will develop after exposure to HPV depends on the individual’s immune system, which may be able to fight off the HPV infection before a wart develops.