Dr. Ian H. Beiser's Podiatry Page
Fungal nails are often yellow, thick and deformed. But the appearance varies widely with the discoloration being brown, green, black or white. This condition occurs when a fungal organism invades the nail, settles in and makes itself at home there. When we typically hear the word infection, we often think of an associated inflammatory response with signs and symptoms such as pain, fever,redness, heat, swelling and pus. However, unlike bacterial infections and acute fungal infections of the skin, onychomycosis is generally not inflammatory (although in some cases, the skin around the nail may become quite inflamed [see paronychia]). Classically, onychomycosis has been characterized by an infection of a certain species of yeast (Candida) or one of the 'dermatophytes' (certain species of fungi that feed off of skin and skin structures such as toenails). However, recent studies have shown that many other types of fungi are now also common pathogens causing onychomycosis.
Fungus often causes the nail to become extremely thick (onychauxic) and deformed. This can result in nails which are very difficult to cut. Thick nails are not always the result of fungus. Trauma to the nail (such as dropping a heavy object on the toe) may result in permanently thick, deformed nails. Thick, deformed nails may start curling around if not trimmed, resulting in a "ram's horn" appearance (onychogryphosis).In some of these cases, the nail edge may cut into the flesh of the toe.
Historically, fungus in the toenails has been very difficult to eliminate. Although it is often caused by the same organisms (e.g. one of the dermatophytes) that causes athletes foot, it is resistant to treatment due to the anatomy of the nail. Because of the lack of blood supply and thickness of the nail, topical antifunguals( such as Lotrimin Cream, Tinactin or Micatin) are not effective. Older oral medication such as griseofulvin have failed to provide a lasting cure. Newer oral agents such as Lamisil (terbinafine) and Sporonox (itraconazole) have recently been approved by the FDA for the treatment of fungal nails. Although they do not provide a cure 100% of the time, the cure rate is significant, greater than 50%, which is certainly beats a historical cure rate of close to 0% . One should also not that these pills are not cheap. The cost of 3 pulses of Sporonox or 3 months of Lamisil may run about $600.
After being ingested, the medication in the anti-fungal pills travels through the bloodstream to the matrix of the nails (where new nail is created) The medication thus works only on newly created nail and not on any previously existing nail. Since the nail may take 9 months to a year to grow from the matrix to the tip of the toe, it may often take a year to obtain a complete cure. Fortunately, the medication deposits itself in the area around the nail matrix where it persists for several weeks or months, depending on which medication is used. Therefore, although it may take a year to treat the entire toenail, the medication only needs to be taken for a fraction of that time. Originally, Lamisil and Sporonox were approved to be taken once daily for 3 months. However, more recently, Sporonox has been approved to be taken as pulse doses (twice daily for 1 week, followed by 3 weeks without any medication and repeated 1 week per month for 3 months in a row). Pulse dosing also has the benefit of lowered side effect risk since the medication is only traveling through the blood stream in high concentrations for 1 week at a time instead of months on end. There are a few known drug interactions.
These medications have not been tested with pregnant women and Sporonox and Lamisil should not be used to treat fungal nails in women who are pregnant or contemplating pregnancy.
How effective are these drugs? That depends on how you measure
efficacy. The efficacy of these medications has been measured in at least 3 different
ways. The information below is taken from studies sponsored by the drug manufacturers:
Overall success or
Effective Treatment- Mycological cure plus clear or minimal nail involvement
and significantly decreased signs
Mycological cure plus Clinical cure with clearance of
Some things to consider about the above statistics:
1. The Sporonox results are based on 200 mg continuous daily dosage rather than 400 mg pulsed dosage. More recent studies have shown that the higher dose taken in pulses is more effective than the prior studies which used the lower daily dosage of 200 mg.
2. These studies relate to treatment of fungal nails caused by the dermatophyte organisms. If studied to include all organisms affecting the toenails, Sporonox would probable come out much better due to it's broader spectrum of activity.
Comparison of Sporonox and Lamisil for treatment of fungal toenails
The most common side effects reported for both medications are Gastrointestinal, e.g. Diarrhea, nausea, upset stomach. When taken continuously for more than one month, both may result in elevation of liver enzymes, approx. 3 or 4%. Other side effects noted are rash, approx. 3% and headache. Lamisil may cause a loss of taste about 2% of the time and may also cause visual disturbances more rarely. Other side effects occur less frequently.
Surgical methods are also utilized at times (although less commonly since the advent of the newer oral antifungals). One such method involves the removal of the entire toenail(s) followed by application of a topical antifungal medication to the toe until the nail regrows. This may take close to 1 year. There is still a fairly high recurrence rate with this procedure. There is also the risk of an ingrown toenail as the nail regrows. The nail matrix could also be damaged when the nail is removed, resulting in a chronically thick or deformed nail. The procedure itself is done under local anesthesia and is painless.
Another option which may be considered when there is considerable thickness or deformity of the nail is permanent removal of the toenail. Even if oral antifungal therapy is effective in removing the fungus, the damage that the fungus has inflicted on the nail matrix is permanent and nail deformity and/or thickness persists. The procedure is identical to the previously described procedure except that following removal of the toenail, a topical chemical (such as phenol or sodium hydroxide) is applied to deaden the nail matrix ("root" of the nail). A layer of skin forms over the nail bed in the place of the toenail. The lack of a toenail is mostly a cosmetic issue and does not result in any significant loss of function or protection. The procedure is painless and there is usually no significant pain after the surgery. There may be some tenderness if something touches the surgical site for the first few days after surgery. Pain medication is usually not needed. There is often mild drainage that could persist for a few weeks. A Band-Aid is usually all that is required until the drainage stops and the toe is covered with a new layer of skin where the nail had been.
Laser treatment for fungal nails
There are currently several different types of Lasers being used to try to destroy the fungus in affected nails. While several of these lasers are cleared for use by the FDA for this purpose, this clearance is mostly an assurance of safety and not necessarily an assurance that the treatments are effective. None of the major insurance companies cover Laser treatment for fungal toenails which often costs several hundred dollars per treatment with no guarantee for success. It may take at least three of these treatments and several months to clear the nails of fungus and there are no long term studies showing that there is a lasting cure.
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