Plantar wart

What Happens

The human papillomavirus invades, causing an inward-growing wart. Warning signs: (1) black specks, (2) pain when you press from side to side, and (3) a disruption of the fingerprint-like lines across your sole, says New Jersey podiatric surgeon George F. Wallace, D.P.M.

Prevent It

Viruses thrive on moist, warm surfaces, such as swimming pool decks. Dr. Wallace suggests wearing sandals until the minute you step in for a dip, and then putting them back on as soon as you step out.

Fix It

Start with an over-the-counter product containing salicylic acid, such as Dr. Scholl's Clear Away Plantar Wart Remover ($10, drugstore.com).

Athlete's foot

What Happens

You can catch this fungus by going barefoot on an infected surface.

Prevent It

Dry your feet after swimming and wash them immediately after playing sports. Wear socks if someone at home is infected, and wear sandals in communal areas (such as showers), says Mahmoud Ghannoum, Ph.D., director of the center for medical mycology at Case Western Reserve University.

Fix It

Ghannoum recommends applying a cream containing an antifungal such as terbinafine (Lamisil AT) every day for a week or two.

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