Classification and external resources
|Warts on the big toe|
A wart is generally a small, rough, abnormal growth (tumor), caused by a contagious viral infection of the skin (typically) or mucous membrane. They commonly infect the surface layer of the hands and feet, but may also occur on the face and genital areas, among other surfaces, such as inside the mouth (Brodsky 2006). Warts can be passed from person to person or from one area of a person's body to another part (Brodsky 2006), whether by direct physical contact or secondary contact with the shed skin of a wart (such as via a towel or floor) (Skinner and Frey 2005).
The viruses causing warts are classified as part of the group of DNA-based viruses known as human papillomaviruses (HPV). Warts are not cancerous, but some HPV strains are linked to cancer formation (Skinner and Frey 2005). Warts typically disappear after a few months but can last for years and can reoccur.
About seven to ten percent of the population has a problem with warts, particularly among children, women, and young adults (Skinner and Frey 2005). As with other infections, the prevention and spread of warts is tied to personal responsibility. Their spread can be lessened by such preventive actions as proper hygiene, avoiding nail biting, wearing shoes, keeping feet clean and dry, exhibiting care regarding shared items, keeping one's immune system healthy (good diet, avoiding stress, and, in the case of genital warts, recognition that spread is tied to promiscuous sexual relations (Skinner and Frey 2005).
Warts are caused by viruses of the human papillomavirus family of viruses. Papillomaviruses are a diverse group of non-enveloped, DNA-based viruses that infect the skin and mucous membranes of humans and a variety of animals, ranging from birds to manatees (Moreno-Lopez et al. 1984; Rector et al. 2004; Campo 2006). Over 100 different human papillomavirus (HPV) types have been identified. Some HPV types may cause warts, while others may cause a subclinical infection resulting in precancerous lesions. All HPVs are transmitted by skin-to-skin contact.
A group of about 30-40 HPVs is typically transmitted through sexual contact and infect the anogenital region. Some sexually transmitted HPVs may cause genital warts. However, other HPV types which may infect the genitals do not to cause any noticeable signs of infection.
Papillomaviruses replicate exclusively in body surface tissues such as the skin, or the mucosal surfaces of the genitals, anus, mouth, or airways (Doorbar 2005). Most papillomavirus types are adapted to infection of particular body surfaces. For example, HPV types one and two tend to infect the soles of the feet or the palms of the hands, respectively, where they may cause warts (de Villiers et al. 2004).
A range of different types of wart have been identified, which differ in shape and site affected, as well as the type of human papillomavirus involved (Anderson et al. 1998). These include:
Many times warts do not need treatment, since many disappear spontaneously (67 percent over a period of two years), particularly in the case of flat warts (Skinner and Frey 2005).
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 percent observed with salicylic acid compared with 48 percent for placebo in six placebo-controlled trials including a total of 376 participants (Gibbs et al. 2003). 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 in many nations. 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 over-the-counter product 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.
Over-the-counter cryosurgery kits are also available, however they can often cost three times as much as the previously named products.
Like prescription treatments, over-the-counter treatments usually require multiple applications and are only necessary if the warts are problematic. Additionally, these treatments are capable of destroying healthy skin as well as warts, so caution must be exercised by those attempting them without medical supervision.
Aromatherapy treatments aim to kill the virus with an appropriate essential oil, such as onion and garlic oils, as well as tea tree oil (Skinner and Frey 2005). Herbal remedies include extracts of plants form the Euphorbia family, juice of a sour apple, fresh banana skin, juice of white cabbage, juice of the dandelion, and rubbing of a raw clove on the wart every night (Skinner and Frey 2005).
Other household remedies include the application of such common household items as a bruised garlic, unskinned potatoes, potato or cauliflower or tomato juice, or other food products like vinegar, salt, or vegemite. Other common household products used include hot water and washing liquid, aerosol sprays or compressed air, and tempera paint. Oils and saps from milkweed, poison ivy, Thuja occidentalis, and fig trees have also been used. Accounts vary in regards to how long these remedies must be applied with each session and how long they take to work.
Duct tape occlusion therapy involves placing a piece of duct tape (or medical tape) over the affected area for a week at a time. The procedure is otherwise identical to that of using salicylic acid adhesive pads. One study by Focht et al. (2002) found that the duct tape method was 85 percent effective, compared to a 60 percent success rate in the study's cryotherapy group. Another study by Wenner et al. (2007), however, found no statistically significant effect in a double-blind, randomized and controlled clinical trial in 90 adults when duct tape was compared to mole skin.
As there have been no controlled studies for most household remedies, it is impossible to know if warts that disappear after such treatments do so because the treatment was effective, or because warts often disappear due to the individual's own immune system regardless of treatment. The evidence that hypnosis may effectively treat warts suggests that the condition may be amenable to the placebo effect, that is, that belief in a remedy rather than any property of the remedy itself is what's effective (IHL).
Some household remedies are potentially dangerous. These include attempts to cut or burn away the warts. Incense is sometimes used in Asian countries to burn warts. These methods are very painful, and can lead to infection and/or permanent scarring.
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