Ask Dr. K: Straight-across cut can prevent ingrown toenails

An ingrown toenail is a common source of foot pain. When the side of the nail digs into the skin, the result is pain, irritation, swelling and redness. Swelling and redness, in turn, can be signs of infection. Your toe may also hurt more when pressed and be warm to the touch.

The big toe is most often affected, but no toe is immune. The problem usually develops because the nails have not been trimmed properly. I wasn’t very good about keeping my toenails trimmed when I was younger, but it didn’t seem to matter: The nails didn’t start attacking the skin. However, once I got to age 40, I noticed that I had to be careful about trimming the nails regularly.

Overly tight shoes are also a factor in producing ingrown toenails. This is more of an issue for women who wear shoes that are very narrow in front. Shoe leather constantly pressing against a nail can change its shape as it grows.

Usually you can treat an ingrown toenail at home. First, soak your feet in warm water to soften the nail. Then cut the part of the nail that is pressing against the skin. Trim gently, not aggressively, or you may hurt yourself.

Once that part of the nail is removed, apply an over-the-counter topical antibiotic. If there is an infection, it may respond to the topical treatment. Wear open-toed sandals or roomy shoes to reduce pressure on the toe.

If your toe isn’t better in three to five days, see a foot-care specialist. Your toe may be infected, and you may need to start antibiotic pills (which treat deeper infections in the toe) and have the ingrown portion of the nail removed.

If you have a recurrent ingrown toenail, your doctor can remove the part of the nail that causes the problem. This procedure can be done in the office, using chemicals.

Do not treat an ingrown toenail at home if you have diabetes. Diabetes can impair your circulation, interfering with your body’s natural ability to heal and fight infection. If you have diabetes and an ingrown toenail, see your doctor or foot-care specialist immediately.

You can prevent ingrown toenails with a few simple measures. Cut your toenails straight across, rather than rounding off the corners. Use a toenail clipper (which is wider and larger than a fingernail clipper). Also, clean under your toenails regularly.

Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.