How To Reshape And Repair Thick Fungused Toenails/

M.D.

Elizabeth Ko, M.D. and Eve Glazier, M.D.

Dear Doctor: I've tried all the toenail fungus cures in our drug store, and so far nothing works. Why not? What can I do? I really miss wearing sandals.

Dear Reader: You are one of the estimated 6 million people in the United States struggling with toenail fungus. It's not only common, but, as you've learned, it's a challenge as well. That's because, although the symptoms affect the visible part of the toenail, the fungi causing the infection actually live underneath the toenail.

Toenail fungus is usually caused by one of a group of microscopic organisms called dermatophytes. Like the yeasts and molds they're related to, these fungi absorb nutrients from organic substances. In the case of toenail fungus, the food source is the portion of the toenail known as the matrix. It's found at the base of the nail, beneath the cuticle. The matrix is served by a network of nerves and blood vessels, and it generates the cells that become the new growth of the toenail. Although this type of fungal infection can affect the fingernails as well, it's more common in the toenails due to the warm, moist and dark environment provided by socks and shoes.

A fungal infection in the toenails typically begins with discoloration, often in a brown or yellowish hue. As the nail grows, it may become thick, malformed and crumbly. The infection is hard to treat due to the makeup of the nail, which is a tough, close-knit protein known as keratin. Some of the topical creams and liquids available at your local drug store can make the nail look better. However, keratin isn't porous, so even medications that advertise themselves as antifungal can't reach the infection. Even as your nails protect your tender toes, they shield the infection. The success rate of these types of medications is quite low.

Many people have good results with systemic medications, which are available by prescription. You take a pill, your digestive system releases the medication and your circulatory system delivers it to that network of blood vessels in the nail matrix that we discussed earlier. These types of meds can have side effects, which range from headache and stomachache to liver damage. When taking a systemic antifungal, it's important to monitor liver function via regular blood tests. Nail growth is slow, which means treatment is a lengthy process. Oral treatment for toenail fungus typically takes three or four months, but it can take a year or more for toenails to look normal again.

Newer treatments for toenail fungus include a prescription topical liquid and laser treatment. Each of these approaches have had mixed results. We've discussed toenail fungus here before, and we have heard from many readers about their own preferred home remedies. These include daubing the affected nails with Vicks VapoRub and with tea tree oil. Clinical trials have shown that these novel treatments, while not a complete cure, may have a positive effect. We recommend that you check with your family doctor about which treatment would be best for you.

Eve Glazier, M.D., MBA, is an internist and associate professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and assistant professor of medicine at UCLA Health.