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Wart
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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.
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Encyclopedia
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.
Cause
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.
Types of wart
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
- Common wart (Verruca vulgaris), a raised wart with roughened surface, most common on hands and knees;
- Flat wart (Verruca plana), a small, smooth flattened wart, tan or flesh coloured, which can occur in large numbers; most common on the face, neck, hands, wrists and knees;
- Filiform or digitate wart, a thread- or finger-like wart, most common on the face, especially near the eyelids and lips;
- Plantar wart (verruca, Verruca pedis), a hard sometimes painful lump, often with multiple black specks in the center; usually only found on pressure points on the soles of the feet;
- Mosaic wart, a group of tightly clustered plantar-type warts, commonly on the hands or soles of the feet;
- Genital wart (venereal wart, Condyloma acuminatum, Verruca acuminata), a wart that occurs on the genitalia.
Treatment
Prescription
 - Application of podophyllum resin paint [podophyllum resin I.P.'66 (20% w/v), benzoin I.P. (10% w/v), aloes I.P. (2% w/v), isopropyl alcohol I.P. to make (100% v/v)]
- Keratolysis, removal of dead surface skin cells usually using salicylic acid, blistering agents, immune system modifiers ("immunomodulators"), or formaldehyde, often with mechanical paring of the wart with a pumice stone, blade etc.;
- Cryosurgery, which involves freezing the wart (generally with liquid nitrogen), creating a blister between the wart and epidermal layer, after which the wart and surrounding dead skin falls off by itself. An average of 3 to 4 treatment is required for warts of thin skin. Warts on calloused skin like plantar warts might take dozens or more treatments.
- Surgical curettage of the wart;
- Laser treatment - often with a pulse dye laser or carbon dioxide (CO2) laser. Pulse dye lasers (wavelength 582nm) work by selective absorption by blood cells (specifically haemoglobin). CO2 lasers work by selective absorption by water molecules. Pulse dye lasers are less destructive and more likely to heal without scarring. CO2 laser works by vaporizing and destroying tissue and skin. Both laser treatments can be painful, expensive, and can cause scarring. CO2 lasers will require local anaesthetic, while pulse dye laser might need conscious sedation. It takes 1 to 4 treatments.
- Infrared coagulator - an intense source of infrared light in a small beam like a laser. This works essentially on the same principle as laser treatment. It is less expensive. Like the laser, it can cause blistering pain and scarring.
- Imiquimod, a topical cream that helps the body's immune system fight the wart virus by encouraging interferon production. Not approved by the U.S. Food and Drug Administration (FDA) for common warts. The drug is expensive, and the response is very poor as compared to genital warts.
- Injection of Candida, mumps, or Trichophyton antigens at the site of the wart, which stimulates the body's immune system;
- Cantharidin, a chemical found naturally in many members of the beetle family Meloidae which causes dermal blistering. Either used by itself or compounded with podophyllin. Not FDA approved, but available through Canada or select US compounding pharmacies.
- Bleomycin, not US FDA approved. One or two injections used. It can cause necrosis of digits and Raynaud syndrome This drug is expensive, USD $200-300 per vial.
- Dinitrochlorobenzene (DNCB), like salicylic acid, this is applied directly to the wart. Studies showed this method was effective with a cure rate of 80% compared to 38% for a placebo. But DNCB must be used much more cautiously than salicylic acid; the chemical is a known mutagen, able to cause genetic mutations. So a physician must administer DNCB. This drug induces an allergic immune response resulting in inflammation that wards off the wart-causing virus.
- Fluorouracil, which inhibits DNA synthesis, is being used as an experimental treatment. It is applied directly to the wart (especially plantar warts) and covered with, for example, tape. This treatment is combined with the use of a pumice stone, but tends to work very slowly.
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.
Over-the-counter
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
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.
Prevention
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.
See also
External links
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