Wiping out toenail fungus
By the faculty of Harvard Medical School for The Harvard Medical School Adviser

Q: What's the best way to get rid of toenail fungus?

A: Toenail fungus, which leads to unsightly, thick yellow nails, can be tough to treat. But several medications can wipe out this stubborn infection, and new treatments are on the horizon.

Sweaty socks and shoes provide the perfect environment for fungi to grow. The itchy, scaly rash found between the toes and on the soles of the feet, known as athlete's foot, is an example of a fungal infection. For athlete's foot, o v e r-the-counter creams and sprays, such as clotrimazole (Lotrimin) and terbinafine (Lamisil) will clear up most cases.

But when fungi infect the toenails, they're much harder to treat. The fungi that cause skin and nail infections are known collectively as dermatophytes. When they get underneath a toenail, dermatophytes feast on the proteins in the nail (see illustration). The result is a yellow, thick and brittle nail. The nails of the big and pinkie toes are affected most often.

Smearing an antifungal cream on a toenail won't help. The cream can't penetrate the nail to reach the fungi in and under the nail. You can try ciclopirox (Penlac) in a form that's applied like nail polish. But it's only for mild to moderate cases and doesn't work very well. Studies have shown that only 1 in 15 people gets clearer nails from the treatment. And the infection often comes back after the treatment has stopped.

But you can take antifungal medications by mouth, which eventually get to the fungus through the bloodstream. Several years ago, a report that pooled the results from a number of different studies found that newer antifungal drugs, which include terbinafine and itraconazole (Sporanox), have a cure rate of about 50 percent. But these medications have three major drawbacks. First, you'll probably need to take the drug for many months. Second, these medications are broken down in the liver and pose a slight risk of liver damage. People taking an antifungal drug need a blood test a few weeks after starting the drug to make sure it isn't harming the liver. And third, these drugs are very expensive, and they're not covered by many insurance plans. All in all, many people decide to just live with their funny looking toenails instead of trying a costly treatment that may not work.

However, Harvard researchers are testing two treatments that would take a more direct route to the fungi. One experimental treatment involves the use of short-wavelength light that's strong enough to shine through translucent nail tissue. The light stops the fungi's growth. The early results are promising, and patients feel only a slight sensation of warmth from the light.

The other treatment involves cutting tiny holes in the nail. If you've ever banged the end of a finger or toe, you know how painful it can be when blood gathers under the nail and pushes on it. Doctors can treat this pooled blood (known as a hematoma) by making holes in the nail so the blood can escape, relieving the pressure. Attacking toenail fungus this way involves rubbing antifungal cream into the holes so it reaches the fungi. Patients can apply the cream at home themselves. The tricky part is making the holes deep enough so the cream is effective, while not going too far and penetrating the nerve-laden soft tissue underneath. The Harvard researchers have used a new instrument with sensors that detect a change in resistance so it knows precisely how far to drill down. They hope to report results from the trial later this year.

Two important cautions: First, insurance companies tend to view toenail fungus as a cosmetic problem. They have a point, since the fungus never spreads to other tissues and does not lead to other health problems. You may end up footing the bill for treatment, be it new-fangled or an old standby. Second, people tend to assume that all deformed nails are caused by toenail fungus. But other conditions, such as psoriasis and eczema, can also affect nails. Be sure you have a definite diagnosis before starting any treatment. One way or another, once you understand the problem, chances are you'll be able to give your toenail-fungus worries the boot.

Copyright 2007 the President and Fellows of Harvard C o l l e g e . Developed by Harvard Health Publications (www.health.harvard.edu ). Distributed by UFS. Submit questions to havard_adviser@hms.har vard.edu.