Onychomycosis is the medical term that is used to describe a fungal infection of the toe or
finger nail. It is estimated that 40 million
Americans suffer from onychomycosis. The organism that causes
onychomycosis is usually fungus (90% of cases) or yeast (7% of
cases).
Onychomycosis is a fungal infection that is unrelated to foot
hygiene. No matter how clean you keep your feet, you are still at risk for a
fungal infection of the skin and nail. There are several ways in
which we contribute to the onset of onychomycosis. First, as a civilized
society we wear shoes. Shoes create an environment that is wonderfully
conducive to the growth of fungus. The environment inside a shoe is dark,
warm and damp. That environment is perfect for the growth of fungus.
Second, any form of trauma to the nail will enable fungus to enter the space
beneath the nail and begin an infection.
It is safe to say that 50% of folks over the age of 50 show
clinical signs of onychomycosis. But this doesn't necessarily
mean that
onychomycosis is due to 'old age'. This simply implies that with the
passage of time there is a greater tendency to acquire a fungal infection of the
nail. Trauma makes the nail much more susceptible to
fungal infections. An injury to the nail is a common precursor to a fungal nail
infection. It's also reasonable to assume that folks in
professions that abuse their feet would tend to have a higher rate of
onychomycosis. Trauma may be something abrupt such as a can of soup
hitting the nail from the top shelf or something as benign as a pair of
ill-fitting shoes constantly rubbing on the nail. Onychomycosis
is also very common in runners.
The appearance of onychomycosis can vary but most cases begin at
the distal tip of the nail and slowly progress into the nail over a period of
months to years. This classic onset of onychomycosis is called distal subungual
onychomycosis. The nail will thicken as the fungus continues to grow. The
filaments of fungus take up space in the nail causing it to swell. The nail can
be yellow, white or even green to black. The nail also begins to be chalky,
flakey and will separate from the underlying nail bed.
Treatment of toe nail fungus and onychomycosis
Prevention of injuries to the nail is a very important aspect of
preventing fungal nail infections.
Preventative measures include:
-
Avoid injuries to the nails. Protect the feet with
enclosed shoes or steel toe boots.
-
Keep the feet dry with frequent changes of socks and use of
talc or baby powder. Rotate shoes to let them dry for 48 hours between
use.
-
Purchase shoes with a toe box the shape of your foot.
When purchasing shoe, stand barefoot next to the new shoes and see how the
shape of your foot compares to the toe box of the shoe. Try to match
the shape of the toe box to the shape of your foot.
Medications for onychomycosis fall into two categories;
topical and oral. There are any number of effective
topical
antifungal medications
available over the counter. Topical medications are most helpful in
treating early infections and for maintaining clear nails. Topical medications
are fungistatic meaning that they inhibit the growth of the fungus. By
limiting the growth rate of the fungus, the nail is then able to grow faster
than the invading fungus infection. Remember,
fungus doesn't take a day off. Compliance is a big issue when using
topical antifungals. It can often take several months before results are seen.
The older generation of oral antifungal medications, which
includes medications such as Fulvicin or Griseofulvin, have been used successfully for years and are making a
comeback due to their economic value. The newer generation of oral
antifungals, including Sporanox and Lamisil, have been received very well by the
medical community. These medications should only be taken under the care of your
doctor due to potential hepatic toxicity.
It's important to note that one of the characteristic findings of
fungal nail infections is the separation of the nail from the underlying nail
bed. Topical and oral medications are in part limited in their efficacy in
that they can treat the fungal infection of the nail but they are not able to
reattach the nail to the nail bed. Separation of the nail from the nail
bed occurs in advanced cases of onychomycosis. Therefore, the success or
failure of these medications in their ability to return the appearance of the
nail to 'normal', can be limited by how advanced the nail infection is at the
onset of treatment.
When all else fails, the fungal toe nail can be permanently
removed. This procedure is an office based procedure and most patients
return to their normal shoes in just a Band-Aid within 24hrs. The removal of
the fungal to nail is permanent. Following permanent avulsion of the nail, the
operative site heals over with skin that can be painted with nail polish as seen
at left.
Which treatment choice is right for you? Consider the following
two examples;
Case 1. Sandy is a 24 year old hairdresser who has intimate
hands on contact with her clients on a daily basis. She has developed a
fungal infection in several of her finger nails. She is concerned that the
fungal infection will have a direct impact on her livelihood and does not want
to spread the infection to others. In this case, Sandy's fungal infection
may directly affect her job. In this case, the use of an oral antifungal
may be indicated.
Case 2. Joe is a 62 year old farmer and has a long history of
injuries to his hands and feet. His last visit to the doctor showed signs
of an increase in his liver enzyme studies indicating an overall decrease in his
liver function. Joe has developed onychomycosis in most of his toe nails.
Joe would not be a candidate for oral antifungal medications. In fact, Joe
may not be a candidate for treatment at all. Periodic debridement of the
nail may be all that is necessary.
Case 3. Irene is a 42 y/o single mom who works in an office
setting. Recently she has noticed a yellow discoloration of several of her
toenails. Irene is beginning to see the onset of onychomycosis.
Irene would be a great candidate for
topical antifungal nail medications.
