Warts (Papilloma; Verrucae)

At least 50 different skin growths are classified as warts. All are caused by strains of the human papillomavirus (HPV), which infect the skin's epithelial cells, prompting them to multiply abnormally fast. The virus can be passed readily from person to person by direct contact.

The most prevalent are verrucae vulgaris, also called common warts. From time to time, almost everyone has one or more of these benign growths, which are easily identified by their appearance. They usually develop on the fingers, elbows, knees, or face. Other types of warts include: Filiform warts, long, narrow growths on the face, neck, or eyelids. Flat warts, usually multiple, which tend to develop on the face, back of the hands, neck, or chest. They are often spread by scratching or shaving. Laryngeal papillomas, which develop on the larynx in infants following vaginal birth or in adults due to oral sex. Pedunculated warts, which resemble a cauliflower and usually appear on the head or neck. Periunguaf warts, which develop around the nails. Plantar warts, which form on the soles of the feet, and mosaic warts, which are clusters of small plantar warts.

The majority of warts are benign, but there are exceptions. For example, laryngeal papillomas may become cancerous, and in people with lowered immunity, malignancies may develop in preexisting warts.

Diagnostic Studies and Procedures

Most warts are diagnosed on the basis of appearance and location. Any that are potentially malignant are biopsied.

Medical Treatments

While common warts usually disappear on their own, it may take months or years. These warts are not dangerous, but treatment may be advisable if they are on the hands or other areas where they spread easily. A doctor can quickly remove them by freezing with liquid nitrogen, burning with an electric needle, or performing laser surgery. These methods, however, may result in scarring, and about one-third will recur.

Chemical treatment may be preferable. One approach calls for applying a potent acid, cantharidin (Cantharone), two or three times, then covering the area for seven hours with tape. The wart should come off when the tape is removed; if not, the treatment can be repeated in one or two weeks.

Flat warts are sometimes treated with daily applications of tretinoin (Retin-A), which promotes skin peeling. In stubborn cases, other peeling agents, such as benzoyl peroxide or salicylic acid, are added to the regimen.

Plantar warts are notoriously difficult to get rid of. One treatment calls for wearing tape containing 40 percent salicylic acid for several days; when the wart is soft enough, a doctor can usually pare it away. Several treatments may be needed, however, and these warts also have a tendency to recur. Another approach entails injecting the wart with bleomycin, an anticancer drug. The wart may also be removed surgically.

Alternative Therapies

Folk and home remedies abound. Some work, but none are foolproof.

Herbal Medicine. Daily applications of aloe vera plant juice are said to make a wart disappear in a few weeks. Rubbing the wart with a clove of garlic is another popular herbal remedy.

Naturopathy. Naturopaths advocate placing some mashed fresh fig on the wart for half an hour daily, for two or three weeks. If this doesn't work, other suggested remedies are: Make a paste of grated carrots and olive oil and apply it to the wart for half an hour twice a day. Or dab lemon juice on the wart and cover it with raw chopped onion for half an hour. Do this daily for two or three weeks. Rubbing the contents of a capsule of vitamin E on the wart daily has worked for some people.

Self-Hypnosis and Visualization. These techniques have been credited with removing warts, but proof is lacking.

Self-Treatment

Various nonprescription wart-removal products are available at pharmacies. One is salicylic acid, available in a gel, liquid, or medicated plaster, to remove a common wart with it, soak the wart in warm water for 5 to 10 minutes, dry, apply the acid, and cover with tape for 8 to 10 hours. Remove the tape and gently rub or scrape the wart. Repeat the process until the wart disappears.

If you try to remove a plantar wart yourself, use extra care not to damage surrounding tissue. First soak the affected foot for 10 minutes in 1/2 gallon of warm water to which 2 tablespoons of a mild dishwashing or laundry detergent have been added. Then apply a 40-percent salicylic acid plaster directly over the wart and cover it with tape or a bandage for 48 hours. While the wart is still soft, scrub it vigorously with a toothbrush to peel away the upper layers. Repeat until the wart is gone, which typically takes two weeks. If your feet sweat heavily, wear absorbent cotton socks.

Other Causes of Skin Growths

Moles sometimes resemble warts. Skin cancers may also be mistaken for warts.