Onychomycosis (Fungus Infections of the Toenails and Fingernails)
Patient Information Sheet
What's going ON?
There are over 1,000 species of fungus. Some can infect the nails, but most do not. Trichophyton mentagrophytes is the most common for nail fungus infections. The infection develops slowly over a period of months or years. It usually starts on the outer end of the nail and invades toward the body end of the nail (proximal nail fold).
Fungus of the nail produces a yellow color. The infected portion of the nails gets much thicker. It gives the illusion of the nails growing thicker. What is actually happening is the plant-root-like outshoots of fungus (hyphae) work their way between the clear, compact hard layers of the nail and explode it from the inside. The nail becomes loaded with these roots and spores which can then spread in that nail and eventually to other nails too. Most commonly I see it in the toenails of the great or first toes. But it can occur in any nails. Your nail is not really getting thicker. The fungus is exploding it from the inside and giving the illusion of thickening. Eventually, it becomes crumbly and rotten.
At first, people are unaware of the problem. It goes on for years getting progressively worse. Trimming the nails does not get rid of it. People become aware of athlete's foot that clears up with a topical antifungus cream. However, the athlete's foot keeps coming back. The creams do not clear up the nail infection, and the fungus creeps out of the nails onto the foot and other parts of the body.
When the fungus causes inflammation around the nail or between the toes, the cracks that form can make openings for opportunistic bacteria to invade and cause significant bacterial infection. This is especially true for people with diabetes and other conditions or who are taking medicines that make it hard to fight off infections. Other than that, fungus infection of the nails is not a dangerous problem.
How Do You Get It?
Fungus can come from other people who are infected, from animals, and from the soil. All three of these sources are common. Fungus is all around us. You cannot avoid it. A more difficult question is why are some people more vulnerable to it than others.
My experience with fungus infections of toenails since 1966 has lead me to suspect that it is commonly picked up from the soil or sand at beaches when you step forward in your bare feet. Your toes dig into the sand. A grain of contaminated sand gets shoved under the nail, and then fungus on the grain of sand starts trying to grow.
To avoid this, I encourage you to wear shoes when outdoors. At the beach, leave your socks on so grains of sand don't get stuck under the nails. After visiting the beach or on soil in your bare feet, use a nail file to clean to clean out anything that may have gotten stuck under the nails.
When I was in graduate school, one of my classmates went to the Waikiki beach in Honolulu and collected sand samples from the regular tourist beach. He grew 18 species of disease causing fungi. He also found toxic algae colonies on the coral reef just out from the beach. So getting beach sand stuck under your toenails is an invitation to getting a fungus infection.
How Do You Treat Onychomycosis and Why Is It So Hard To Treat?
Until the coming of imidazole antifungals in the late 1970's, doctors were very hesitant to treat onychomycosis. Consider the standard treatment prior to then. The doctor started by ripping out the infected nails. Yes, it is as gruesome as it sounds. Then the patient took griseofulvin pills daily for 2-3 years. Griseofulvin could damage the liver and bone marrow. People had to be monitored for such damage. But here's the worst part. The cure rate was 30%. It was twice as likely to fail as to succeed. So, you start Griseofulvin treatment knowing the odds are 2:1 against it's working.
Why is it so hard to treat? I don't know. It does not make sense. The biophysics and biochemistry of the nails are such that the nails are very permeable. Yet rubbing or painting topical fungus medicines on the nails does not work. The best topical medicine for onychomycosis is Penlac. Penlac has a (get this) 95% failure rate.
In the late 1970's, ketoconazole pills (Nizoral) became available. I did work with medical mycology professor Mike Rinaldi at MSU. We found that we got good treatment response (not necessarily cure) in 70% of patients. It was twice as likely to work as to fail. Just the reverse of Griseofulvin. For about 10-12 years, this was the standard treatment. Then reports of side effects started to accumulate. About one person in 14,000 would get bad liver damage.
I had a 4-year-old patient with an immune deficiency disease called mucocutaneous candidiasis. He had rampant yeast infections of the mouth, face, and nails. I treated him with ketoconazole, the standard treatment at that time. After 4 months, he turned orange like a pumpkin. You can imagine how worried I was. Fortunately, he recovered just fine. Oddly, he came back after about 10 years, we used ketoconazole again, and he did just fine. I concluded that little kids are at greater risk than teens and adults.
Understandably, I became hesitant to treat onychomycosis. Slowly, over period of years, other, safer pills became available: Sporanox, Lamisil, Diflucan.
Before starting treatment, I like to prove the diagnosis. Is the problem really a fungus? Psoriasis can look very much like onychomycosis. But, it will not improve with the use of these medicines. To establish this point, I do a simple nail scraping and KOH prep to see if fungus is there. Sometimes fungus is present, but hard to see on the lab test. KOH prep is reputed to be more reliable than fungus culture.
- Do nothing. If your body is containing the infection on its own, it could go on for 20 years without much progression. This happened to me on one toenail. I did nothing from 1966-2008. About 2008, it became obvious to me that it was spreading.
- Topical Antifungal Creams. These do not work. Sorry.
- Oral Medicines (pills): Diflucan, Sporanox, Lamisil. You would take one, not several at once. This is called systemic therapy because your body delivers the medicine to almost your entire body. You can argue why should you treat your bones, liver, lungs, muscles, etc. which do not need treatment just for a toenail? This is an exercise in applying your own judgement. I have had one patient who was on nasal oxygen for lung disease. To everyone's surprise, after 6 weeks of toenail treatment, his lungs cleared up and he got off nasal oxygen after 3 months of treatment. He was delighted. His internist found that he had an unrecognized mucormycosis fungus infection of his lungs.
So far, pills are the only things that work. The downside to taking pills is that some are expensive, may irritate the liver, and can conflict with other medir irritation is less likely if you avoid drinking alcohol.
Diflucan and Sporanox are fungistatic. They do not kill the fungus. They stop fungus growth until the nail grows out. The infected nail is replaced by new, uninfected nail. Fingernails grow at a rate of about 0.1mm a day. Toenails grow much more slowly. It can take a year or more of waiting for the infected toenail to be completely replaced by uninfected nail.
Lamisil is fungicidal. It kills fungus. If Diflucan does not work, I often suggest Lamisil. Sometimes it works much better. The problem I have with Lamisil, is that it is more likely to irritate the liver than low dose Diflucan. I have run into that several times. Lamisil may give longer lasting results than Sporanox.
With all these drugs, I recommend trying the medication for 4 months and then re-evaluating.
As of January 2009, here are scores:
Culture Proven Cure Rates (These may or may not correspond to actual cure rates. That is, is the infection really gone? I want to say that cures occurring this fast, just do not happen in my experience. So, although these data are published in peer-reviewed journals, I do not trustthem.)
|Drug taken by mouth||Dose and Duration||Cure Rate|
|Lamisil (Terbinafine)||250mg daily (6 weeks fingernails, 12 weeks toenails)||73-79%|
|Sporanox Pulsed Therapy (Itraconazole)||About 200 mg daily for one week/month. 2 months fingernails, 3 months toenails||56-70%|
|Sporanox Daily (Itraconazole)||250 mg daily||54-63%|
|Diflucan (Fluconazole generic)||150 mg single dose once a week. 4 months fingernails, 6 months toenails||43-53%|
Notice that my favorite (Diflucan) is at the bottom of the list. So why do I prefer it? This is what I have used for my own toenail infection. The thing about Diflucan taken as a single dose once a week is that it is so much cheaper and safer. If that does not work, we can switch to Lamisil. Unless you want to start with Lamisil.
A funny thing about Diflucan and Sporanox is that they are better absorbed if you take them with some acidic drink such as orange juice, tomato juice, or a soft drink such as Coke, Pepsi, 7-up, etc. Lamisil can be taken with water or any drink.
Rev. Jan. 22, 2010 copyright Dr. Tkach
The information provided in these patient information sheets is offered for general informational and educational purposes only; it is not offered as and does not constitute medical advice. In no way are any of the materials presented meant to be a substitute for professional medical care or attention by a qualified practitioner, nor should they be construed as such.