Diagnosing and treating yellow toenails

Onychomycosis is a yellowing of the toenails that often is caused by a fungal infection. Up to 18 percent of the population has this disease at any given time and it tends to get more common with age. Usually it affects the toenails; however, it also can occur in fingernails at the same time. Interestingly, it mostly affects only one toenail at a time.

Multiple studies have looked at potential risk factors that may make a person more susceptible to onychomycosis. Those include increasing age, exposure to damp communal areas such as gyms or swimming pools, poor foot hygiene, impaired immune status, diabetes mellitus, poor peripheral circulation, athlete’s foot and nail trauma.

The disease rarely goes away on its own. The condition also may lead to the nail being lost – either from becoming weak and breaking away or from a person picking it away. The yellowish discoloration and thickening occurs from the dead skin tissue accumulating under the nail in the nail bed, which is where the fungus lives.

Not every yellow nail is from a fungus, however. Studies indicate that up to 40 percent of all discolored, hardened nails may come from other conditions such as psoriasis, eczema, aging changes, trauma or the skin disease lichen planus. Confirming the diagnosis can be aided by a physician scraping from underneath the toenail and looking for a fungus. If the base of the toenail is affected, then one might consider a biopsy of the toenail or even complete removal for evaluation and diagnosis.

There are numerous treatment options available depending on the type and severity of onychomycosis that one has, including:

▪ Terbinafine (Lamisil) – 76 percent cure rate. A 12-week regimen. Depending on what medications and other health problems a patient might have, the patient may need to check liver enzymes initially and halfway through treatment to ensure no damage is happening to the liver from the medication.

▪ Itraconazole pulse therapy – 63 percent cure rate. A three-month commitment. There is no monitoring with this medication.

▪ Fluconazole (Diflucan) – 50 percent cure rate. Typical therapy is once or twice a week for eight weeks then off and repeated if needed. There is no monitoring with this medication.

Topical treatments in the form of a lacquer applied like nail polish exist but have not shown consistent results. One such nail polish is called ciclopirox and is safe to use for a mild disease on the end of the nail itself. However, the cure rate is only one out of 15 patients who use it. Other treatment methods such as laser therapy and surgical removal are still being explored.

Unfortunately, the likelihood of onychomycosis returning is around 30 to 50 percent. This isn’t very encouraging for patients who want to treat this pesky, mostly cosmetic problem. Taking preventive measures is the best defense. That includes wearing footwear in damp, communal areas, keeping toenails short and clean, drying feet immediately after bathing, wearing socks made from absorbent material such as cotton (and changed if wet) and quickly treating symptoms of athlete’s foot.

This story was originally published November 13, 2015 at 7:18 PM with the headline "Diagnosing and treating yellow toenails."