Editor’s Note: “The Nail Doctor” is a monthly health column written by Orville J. Stone, M.D., a dermatologist who specializes in nail diseases. This column is a guide to help you recognize and understand common nail conditions. Remember, however, that your job as a nail technician is to beautify the nails, not to diagnose or treat physician ailments. When in doubt about the nature of a particular nail disorder, you should always contact your state board of cosmetology or a physician.

Warts are a common problem caused by contagious viruses. All warts come from direct or indirect contact with another wart. Each wart makes millions of viruses each day that can be passed to other people and cause warts. Fortunately, only a few of these viruses gain entrance to a skin cell, which is where the virus grows and becomes a new wart.

Scrapes, cuts, or open wounds are especially prone to contamination. A wart virus can lie dormant in apparently normal skin before suddenly emerging. Studies have shown that skin cells infected with a wart virus can remain normal with no warts appear. Inactive viruses may be hiding in skin cells, waiting to grow at a later date.

When I treat warts, I caution the patient that there is a 95% to 98% chance of success that the wart will not return. While regular warts can disappear spontaneously without treatment, warts around or under the nail are more persistent, it’s frustrating to freeze or burn off a wart only to have it recur at the prior site. This happens when the virus is lying dormant in nearby skin cells. Contrary to popular belief, lasers are not a magic answer to treating warts. They are just a fancier – more expensive – way to burn off a wart.

People who have a wart near the nail can develop multiple warts from picking at it. The virus gets under the nail, where a wart can grow or be spread to another part of skin.

Warts near the nail appear on the posterior nail fold, the lateral nail fold, or the distal edge of the nail. These w arts can be removed by a variety of over-the-counter products, or they can be frozen or burned off by a dermatologist. Most over-the-counter products contain keratolytics, such as salicylic acid, which eat away at wart tissue. These treatments must be used faithfully to get results.

New Federal Drug Administration rules now allow wart treatments previously available only prescription to be purchase over-the-counter. These treatments can be effective on warts near the nail but they’re disappointing when wart is partially under the nail and are worthless on warts completed under the nail. I compare their effect to going out in your yard and cutting all the weeds off at level. You’re not rid of them.

You should refer clients with warts partially under the nail to physician. A wart that appears be progressively destroying the nail should be seen immediately by a dermatologist as it may be cancerous growth.

Warts on the posterior nail fold can spread to the lateral edges the nail fold. Warts at either of these sites should be removed a dermatologist before they spread to areas that are harder to treat. The physician burning or freezing off these warts has to be very cautious because vigorous therapy on the posterior nail fold can damage the nail matrix, causing a permanent nail deformity. I have seen many examples of this.

Warts along the lateral nail fold or distal edge of the nail present a special treatment problem. The wart is almost always partially under the nail’s edge. In my opinion, it is extremely difficult to treat these lesions unless the finger is first anesthetized and any nail over the wart is trimmed away. The entire wart  must be visible for successful treatment. I then scrape out the wart tissue and cauterize (burn) the wart’s base. I always warn the patient that the nail plate might not perfectly reconnect to the nail bed after the treatment because of scarring, although I rarely see this problem. I do occasionally see recurrences of the wart that require repeat treatment.

When you’re doing salon cosmetic procedures on clients with warts, make every effort not to break the skin. Also, do work around the wart with your hands or instrument. Wash your hands after servicing the client and sanitize your work surface and tools, disposing of implements such as files that cannot be disinfected.

Recommend a topical treatment for warts around the nail, and refer the client to a dermatologist if the wart is on the lateral or distal nail fold or under the nail itself.

Orville J. Stone, M.D., is a dermatologist practicing in Southern Calif. He has taught at medical schools for 30 years. He has published 150 scientific papers; his first paper on nail disorders appeared in 1962