This condition will afflict up to 48 percent of American adults before they reach the age of 70. And it often signals more serious health problems. The good news is that nearly all cases are easily preventable.

A Growing Problem

The symptoms of toenail fungus are easy to detect. They include thickened or brittle nails, often dull in color with spots of yellow or white and, in more serious cases, brown or black.

Toenail fungus is on the rise for several reasons: It spreads to shower floors, damp pool decks, and even nail salon footbaths. Fungi also thrive inside damp or dirty socks. Sweaty feet in poorly ventilated shoes produce the damp environment that these parasites love.

Normal resistance to parasites on and under the nail depends on healthy oils from the skin surrounding the nail and its root. This, in turn, depends on good blood circulation to the tips of the toes.

Add to this mix an epidemic of diabetic and prediabetic symptoms, one of which is the loss of peripheral circulation. Americans are becoming a nation of undernourished toes, susceptible to fungal infection as never before. A study published in the British Journal of Dermatology finds that diabetes increases the risk of acquiring toenail fungus by almost three times.

Tough as Nails

Keratin is the hard and seemingly inert material that makes up the toenail’s outer layer. Not much nutrient value here, you would think, but to a group of fungi called dermatophytes, lunch is on the table.

Some fungi are parasitic—they exist only on nutrients that have already been produced or stored by some other organism. In the case of toenail fungi, they find enough food value even in keratin to make themselves at home. Because there is no blood circulation within toenails, they are beyond the reach of our blood-borne antifungal defenses.

Natural Solutions

The mainstream medical approach includes antifungal drugs, applied topically or taken orally. Over-the-counter creams can be safe and helpful for mild infections. Prescription treatments are also available but may not always be safe.

Less invasive solutions are obvious: Keep your feet dry, change your socks more often (twice a day is recommended), wear loose-fitting comfortable shoes, use flip-flops at the gym shower or around the pool, and, if at all possible, try to spend some time barefoot around the house (on clean floors) to give your toes some air time. A little direct sunlight every day is probably the best antifungal treatment of all.

Tea tree oil is a natural remedy for a wide variety of skin infections, including fungi. But it is strictly for external use and should never be swallowed or come in contact with the eyes. Although extreme cases of toenail fungus can lead to reduced mobility and coordination, the bigger issue is that toenail fungus could be a sign that there are other problems lurking in the background. For example, check for early symptoms of Type 2 diabetes, and take action to reverse the trend before it becomes a more serious medical condition.