Common warts are firm, well-defined growths up to a quarter inch wide, often with a rough surface. They usually appear in areas that are frequently injured, such as the hands, knees, scalp, and face, especially in young children. They often appear in crops and can disappear spontaneously. Sometimes a few of these bumps run together, but they usually appear separately. Tiny black specks in the wart are caused by tiny clots of blood.
Flat (plane) warts are small (about 1/16 inch) tan, flat, round, and grouped together on the face, backs of hands, and shins.
Digitate warts are dark-colored growths with finger-like projections.
Plantar warts are flat, rough warts that appear on the soles of the feet, flattened by the pressure of the body on the bottom of the foot that forces them to grow inward. They appear alone or in groups. Children aged 12 to 16 are most likely to get plantar warts; younger school-age children are more likely to get common and plane warts.
Genital warts are transmitted through sexual contact and are characterized by pink, cauliflowerlike groups of growths on the genitals. This type of wart needs prompt treatment, since there is some evidence that these warts infecting the cervix may cause cervical cancer.
Warts are caused by one of the more than 58 types of human papilloma virus (HPV); the three kinds that affect children are the common, flat, and plantar wart caused by HPV types 1, 2, 3, and 4. Several other types of HPV can cause genital warts.
A child gets a wart by touching someone else’s wart, touching something a wart-infected person has touched, or by self-inoculation. Children who bite on their own warts can spread them to other areas of their own bodies.
The incubation period averages between two to three months, but it may be as long as 20 months, and the child is infectious as long as the wart appears.
Most warts are diagnosed by appearance; rarely, a doctor may biopsy a piece of wart to make a diagnosis.
More than 65 percent of warts disappear on their own within two years. There is no cure that will remove all traces of the virus from the body. Instead, treatment aims at removing or shrinking the warts, whether by freezing, using a topical solution or a laser, or surgery. Common, flat, and plantar warts may be removed with liquid nitrogen or a blister-producing agent, corroding acids, or plasters. Surgical removal with a scalpel, electric needle, or laser may also be used. Unfortunately, warts often reappear after treatment. In the doctor’s office, liquid nitrogen freezes the wart, forming a blister that lifts off the wart.
Recent research at Children’s Memorial Hospital in Chicago and New York University found that the ulcer drug cimetidine may be an effective treatment of multiple warts in children. Multiple warts can be troublesome because they often resist treatment, such as topical medications, freezing, burning, or laser surgery, or they reappear after successful treatment. In the study, young patients whose warts had not responded to other treatment showed signs of improvement after three daily doses of cimetidine. Within six to seven weeks, many of the warts had become flatter and less visible; two months into the study, warts in almost 80 percent of the children had disappeared. Researchers report that cimetidine is safe for children, and does not appear to cause any side effects.
Over-the-counter removal preparations include topical medications containing SALICYLIC ACID and lactic acid that peels off the affected skin (the virus is killed as well, since it is inside the tissue). The skin should be softened first before applying the medicine; a few times a week, the dead skin should be removed with an emery board.
If the warts do not disappear with this treatment, a dermatologist may apply liquid nitrogen to freeze the wart, forming a blister that lifts off the wart. This takes four to six weeks. Sometimes a blister-producing liquid (cantharidin) or a corroding acid liquid or plaster may be used. Some doctors may use heated electrical needles.
Since wart treatment can be painful and cause scars, many doctors prefer to wait for the warts to disappear on their own.