Sunday, November 22, 2009

Treatment of Fungal Toenail: Fact or Fiction

Onychomycosis is a fungal infection of the toenails or fingernails. The actual infection is of the bed of the nail and of the plate under the surface of the nail resulting in thickening and discoloration of the nail plate along with damage to the underlying nail bed. Onychomycosis is the most common of all diseases of the nails. It’s estimated that in North America, the incidence is as high as 13% and that over 25 million Americans suffer from fungal toenails. The incidence of onychomycosis is also greater in older adults, and up to 90% of the elderly may be affected. Men are more commonly infected than women.

Individuals who are especially susceptible include those with chronic diseases such as diabetes and circulatory problems and those with diseases that suppress the immune system. Other risk factors include a family history, previous trauma to the nails, warm climate, and occlusive or tight footwear.

Onychomycosis is caused by three types of fungi called dermatophytes, yeasts, and nondermatophyte molds. Fungi are simple parasitic plant organisms that do not need sunlight to grow. Toenails are especially susceptible because fungi prefer dark damp places. Swimming pools, locker rooms, and showers typically harbor fungi. Chronic diseases such as diabetes, problems with the circulatory system, or immune deficiency disease are risk factors. A history of athlete's foot and excess perspiration are also risk factors.

There are numerous conditions that mimic the appearance of fungal toenails and it is essential to confirm the diagnosis of fungus prior to initiating treatment. These other conditions include candida, contact dermatitis, lichen planus, psoriasis, subungual tumor, traumatic onychodystrophy, yellow nail syndrome, amelanotic melanoma, granuloma, and melanoma. In order to confirm the diagnosis of onychomycosis, a careful history, clinical examination and culture or microscopic examination of the involved nail should be performed.

Onychomycosis can be present for years without causing pain or disturbing symptoms. Typically, the nail becomes thicker and changes to a yellowish-brown. Foul smelling debris may collect under the nail. The infection can spread to the surrounding nails and even the skin.

Onychomycosis is very difficult and sometimes impossible to treat, and therapy is often long-term. In order for a fungus to grow it must produce a variety of enzymes, proteins which are responsible for acting as catalysts to promote reactions at the cellular level. Current therapy is directed at inhibition of the enzymes within the fungus and consists of topical treatments that are applied directly to the nails, as well as oral systemic drugs. As the fungus overtakes the nail, the nail slowly dies and thickens making it difficult for topical medications to penetrate the nail bed. Subsequent damage to the nail bed results in decreased blood supply making it difficult for oral medications to get to the infection in high enough concentration in order to destroy the fungus. Another factor which makes treatment difficult is recontamination of the nail since the fungus may thrive in the warm moist environment found inside shoes.

Topical therapy is reserved for only the mildest cases and has about a 10-15% cure rate. First and second generation oral antifungals such as griseofulvin and ketoconazole is problematic, and there are typically high relapse rates of 50-85%. In addition, treatment must be continued for a long duration (10-18 months for toenails), with monthly laboratory monitoring for several side effects, including liver toxicity. Individuals taking these medications must also abstain from alcohol consumption.

In the past few years, newer oral antifungal agents have been developed, and include itraconazole (Sporanox), terbinafine (Lamisil), and fluconazole (Diflucan). These agents, when taken orally for as little as 12 weeks, bring about better cure rates and fewer side effects than either griseofulvin or ketoconazole. The most common side effect is stomach upset. Patients taking oral antifungal therapy should have a complete blood count and liver enzyme workup every four to six weeks. Terbinafine in particular has markedly less toxicity to the liver, one of the more severe side effects of the older agents, griseofulvin and ketoconazole.

Due to the relatively low success rate, risk of side effects and high cost of the prescription antifungals, numerous over the counter topical preparations have been developed and touted to purportedly destroy the fungus and restore normal nail growth. There have been no scientific studies to support these findings, only bold claims by their manufacturers and distributors and empirical data from their patients describing their personal experience. These over the counter preparations and therapies include tea tree oil, tea tree oil mixed with lavender oil, Listerine mouthwash, diluted apple cider vinegar, oregano and olive oil mixture, alpha hydroxyl acid creams, baking soda scrub, diluted Clorox bleach and Vick’s VapoRub. In the 29 years that I have been treating onychomycosis I have encountered a number of patients who’ve related stories about a friend or relative who used one of these therapies with success, however, I have never had a patient claim that they personally had success although I have seen some positive results with Thymol and Miconazole (Fungoid tincture).

A new technology has recently been developed using a laser beam of near infrared light to destroy the fungus at the cellular level. This has shown great promise in the treatment of onychomycosis and is currently pending FDA approval for treatment of this condition. Recent clinical studies using this modality have demonstrated a 70-80% cure rate. Anesthesia is not required when performing this procedure, and medications are typically not used in combination with laser therapy, thus minimizing side effects and issues of compliance.

The best advice is to consult with your Podiatrist to confirm the diagnosis of onychomycosis prior to initiating any treatment. Once the diagnosis is confirmed, treatment should consist of medications or techniques that have been scientifically proven to inhibit the growth of the fungus. You should then be examined on a regular basis to monitor for possible side effects and to document the status of your nail condition.

Dedicated to your foot health,
Dr. Paul Yungst, DPM, DABPS

3 comments:

  1. treatment for fungal toenail is a fact.. there are a lot of treatment that really works.. one of it zeta clear..

    What is Yellow Toe Nail Fungus

    ReplyDelete
  2. Toenail fungus is the one that spreads from one person to other if we share the socks or also if we don't wash the socks regularly.... Herbal remedies are the best one to cure it totally...
    toenail treatment

    ReplyDelete