Nail Fungus (Onychomycosis)

 

When we think about nail infections, fungus is probably what first comes to mind.  It turns out that onychomycosis (nail fungus) is extremely common, as an estimated 35 million people in the U.S. are infected. It is important to understand what makes us vulnerable to nail fungus, and why it is important to treat.

Who is vulnerable?

We are all exposed to fungus in our environment, yet, not everyone acquires the infection.  Our vulnerability is dependent on the complex interplay between our genetics, age, other medical issues, habits and the environment.  Older age is a risk factor as more than 50% of cases of nail fungus are seen in those over the age of 70.  As we age our toenails change from years of chronic, repetitive micro trauma.  Once the nail starts to grow abnormally we become vulnerable to acquiring fungus.  A nail that becomes lifted will have an opening where organisms can enter. With age brings slower nail growth, another factor that predisposes to fungal acquisition.  Certain medical conditions make us more susceptible such as diabetes, peripheral vascular disease, psoriasis and HIV.  Toenail trauma, common with certain athletic activities, such as tennis, skiing, and running can lead to onychomycosis.  Once the nail is damaged and lifted away from the nail bed, there is a barrier compromise and fungus in the environment or on neighboring skin can enter the nail unit.  Excessive foot sweating, poor hygiene, and unprotected communal exposure (bare feet in the gym locker room) can also put one at risk.  When heading to the nail salon, always make sure that one-time use items are not reused on multiple clients.  Tools such as toe separators and emery boards should be used once because repeated use from client to client can be result in  fungal transmission.

Why Treat?

For many, nail fungus is cosmetically unappealing and the rationale to treat is purely for aesthetic reasons.  Most do not realize that there are important medical reasons why treatment can be imperative.  For one, fungus can spread to other toenails, the hands, the fingernails or other skin skin sites.  Thick, infected nails can be difficult to maintain and even painful, and can negatively effect the ability to walk.  Fungus at the toenails is also a very common cause of bacterial infections of the skin at the lower legs (lower extremity cellulitis).  This occurs when microscopic breaks in the skin become infected with bacteria.

Treatment options

We can divide our treatment options into three categories: oral agents, topical agents, and nonpharmacologic approaches to therapy.  Oral agents are prescriptions pills such as Terbinafine (Lamisil), Itraconazole, or Fluconazole.  These are medications that must be prescribed by a physician.  We have a lot of experience with these medications as they have been on the market for years.  Dosing and treatment duration depends on the type of fungus and the severity of the case being treated.  These oral medications have had rare but serious side effects associated with them including liver and cardiac toxicity, therefore, laboratory monitoring is important.  Also, these oral agents can interact with other common medications.  For these reasons, many patients and physicians shy away from oral agents and prefer to use topical therapies.

Topical fungal medications are advantageous because they have fewer side effects and do not require laboratory monitoring.  The disadvantage is that they are less effective and patients tend to be less compliant with these treatments because the treatment courses are longer.  Until recently, the only prescription topical antifungal agent that was approved in the US was ciclopirox lacquer (Penlac).  More recently, two new prescription topical antifungals have been approved and have demonstrated superior efficacy.  Efinaconazole 10% solution (Jublia) was approved in June, 2014 and Tavaborole 5% solution (Kerydin) was approved in July, 2014 for the treatment of onychomycosis.  For toenails, treatment is daily for 48 weeks.  Both of these drugs have very safe profiles and are exciting additions to our anti-fungal armamentarium.

Non-pharmacologic approaches to therapy include mechanical nail removal, laser treatment, and chemical removal of the nail.  Mechanical nail removal tends to be a method that is favored by podiatrists. When toenails are extremely thick and it is less likely that a topical medication will be able to penetrate effectively, this can be a beneficial option.  Lasers always have appeal because they are high tech and thought of as the latest in technology.  Currently short-pulse Nd-Yag lasers are approved in the U.S for the temporary increase of clear nail.  These devices are still considered controversial as their efficacy is questionable and many believe that they have not yet been adequately studied.  Chemical removal involves using a Urea based prescription cream and applying it to the nail repetitively.  Urea breaks down keratin and can soften even very thick nails.  Over time the nail will crumble and become easier to remove without the need for surgery.