A wart (also known as verruca) is generally a small, rough tumor, typically on hands and feet but often other locations, that can resemble a cauliflower or a solid blister. Warts are common, and are caused by a viral infection, specifically by the human papillomavirus (HPV) and are contagious when in contact with the skin of an infected person. It is also possible to get warts from using towels or other objects used by an infected person. They typically disappear after a few months but can last for years and can recur.
Warts are caused by a virus called human papilloma virus or HPV. There are approximately 100 strains of human papilloma viruses. Type 1, 2, and 3 causes most of the common warts. Type 1 is associated with deep plantar (sole of the feet) and palmar warts (palm of the hand). Type 2 causes common warts, filiform warts, plantar warts, mosaic plantar warts. Type 3 causes plane warts, or commonly known as flat warts. Anogenital warts are caused by types 6, 11, 16, 18, 30, 31, 33, 34, 35, 39, 40 and others. HPV types 6 and 11 cause about 90% of genital warts cases. HPV types 16 and 18 currently cause about 70% of cervical cancer cases, and also cause some vulvar, vaginal, penile and anal cancers. Gardasil, a vaccine for HPV is designed to prevent infection with HPV types 16, 18, 6, and 11; it is claimed to prevent infections to other strains of anogenital warts through cross protection against other types of HPVs. HPV is associated with oral cancer, laryngeal cancers, tracheal and lung cancers.
A range of different types of wart has been identified, varying in shape and site affected, as well as the type of human papillomavirus involved. These include:
|Two viral warts on a middle finger, being treated with a mixture of acids (like salicylic acid) to remove them. A white precipitate forms on the area where the product was applied.|
Treatments that may be prescribed by a medical professional include:
The wart often regrows after the skin has healed.
One review of 52 clinical trials of various cutaneous wart treatments concluded that topical treatments containing salicylic acid were the best supported, with an average cure rate of 75%, compared with 48% for the placebo in six placebo-controlled trials including a total of 376 participants. The reviewers also concluded that there was little evidence of a significant benefit of Cryotherapy over placebo or no treatment.
There are several over-the-counter options. The most common ones involve salicylic acid. These products are readily available at drugstores and supermarkets. There are typically two types of products: adhesive pads treated with salicylic acid or a bottle of concentrated salicylic acid solution. Removing a wart with salicylic acid requires a strict regimen of cleaning the area, applying the acid, and removing the dead skin with a pumice stone or emery board. It may take up to 12 weeks to remove a wart.
Another product available over-the-counter that can aid in wart removal is silver nitrate in the form of a caustic pencil, which is also available at drug stores. This method generally takes three to six daily treatments to be effective. The instructions must be followed to minimize staining of skin and clothing.
Cryosurgery devices using freon refrigerants are inexpensive. A disadvantage is that the sponge applicator is too large for small warts, and the temperature achieved is not nearly as low as with liquid nitrogen. Complications include blistering of normal skin if excess freezing is not controlled.
Duct tape occlusion therapy (DTOT) involves placing a piece of duct tape over the wart(s) for six days, followed by soaking the area in water and scraping it with a pumice stone or emery board. There is conflicting evidence as to whether or not DTOT is an effective wart therapy.
The study cited above had 9 patients lost to the follow-up from the original 61 patients entered. In contrast to the flaws (15% of subjects lost to the follow-up) and favorable results of the above study, a more stringent study of 103 children found no benefits from transparent duct tape. The evaluators were blinded during treatment for the most part, a placebo (corn pad) was used and there were no patients lost to the follow-up. After six weeks, rates of wart resolution were similar in the duct tape and corn pad groups and much lower than the rates seen in the earlier trial.
A similar trial comparing duct tape with a control treatment with a moleskin pad in 90 adults also found no difference in the rate of wart resolution at the end of two months (21 versus 22 percent). However, the median age in this study was 54 years, and transparent duct tape was used, which contains no rubber found in the standard gray variety.
Gardasil is a vaccine aimed at preventing cervical cancers and anogenital warts. Gardasil is designed to prevent infection with HPV types 16, 18, 6, and 11. HPV types 16 and 18 currently cause about 70% of cervical cancer cases, and also cause some vulvar, vaginal, penile and anal cancers. HPV types 6 and 11 cause about 90% of genital warts cases.