The Fungus Amongst Us

Dear Lucy: I have a shadow area inside one of my big toenails, and I think it is toe fungus. The fungus appears to be “under” the nail. Interestingly, this appeared after I removed toenail polish after almost two constant months of wearing it. Does nail polish block access to sun and air and thus promote toe fungus? Can I apply Lamisil externally around the area, and will that do the trick? Also does putting one’s feet in the salt water of the ocean help—as some sort of natural disinfectant, perhaps? —Toe Troubles

Dear Toe Troubles: As MIT Medical Dermatologist Allison Larson said when Lucy forwarded your letter to her, “That is definitely more than one question!” Fortunately for all of us, Larson was more than up to the task of answering each one, including the one you didn’t ask—“Is it actually toenail fungus?”

“Probably” is Larson’s answer. “A lifting toenail is often—though not always—caused by toenail fungus, she says. “But sometimes bacteria can colonize the area and contribute to discoloration as well.” 

As for treatment, “unfortunately, topical Lamisil is rarely successful when fungus involves the nail plate itself,” Larson notes. But, she says, there’s no harm in trying the topical medication, which is available without a prescription, as a first approach. “However,” she adds, “in addition to applying it on top of the nail, try to apply it to the underside of the lifted portion where more of the fungus is residing.” Larson also recommends using a topical antifungal between your toes, as this is a common reservoir for fungus on the feet. 

If topical Lamisil does not work, you might want to speak with your primary care provider about oral Lamisil (terbinafine), which requires a prescription. “Oral Lamisil is more successful than the topical treatment for fungal infections of the nail,” Larson says, “but it has potential side effects and most people who undergo this treatment will become re-infected at some point.”

As to your toenail-polish question, Larson notes that while polish may dry out the toenails, causing discoloration and altered nail texture, it does not—in and of itself—make fungal infections more likely. “However,” she emphasizes, “it is quite common to pick up a fungal infection at a nail salon”—pedicure devotees, take note! 

Finally, while it would be lovely to write off a seaside vacation as a medical expense, Lucy is sorry to inform you that, according to Dr. Larson, salt water has no medicinal properties when it comes to treating toenail fungus. On the other hand, Larson tells Lucy that although water salinity is irrelevant, soaking nails prior to applying topical medication may enhance the medication’s ability to penetrate the nail, making it somewhat more effective than it might otherwise have been.

Here’s to a fungus-free future! —Lucy

Back to Ask Lucy Information contained in Ask Lucy is intended solely for general educational purposes and is not intended as professional medical advice related to individual situations. Always obtain the advice of a qualified healthcare professional if you need medical diagnosis, advice, or treatment. Never disregard medical advice you have received, nor delay getting such advice, because of something you read in this column.