Keys To Managing Severe Onychomycosis

Author(s): 
Myron Bodman, DPM

   Gupta reports one can use terbinafine safely in children and the elderly.23 However, clinicians should always exercise caution in patients with major polypharmacy. It may be best to use alternate therapy in these cases to avoid adverse drug reactions in patients with an essentially benign disease.

A Closer Look At Topical Therapy Agents

Oral therapy is the most effective therapy for severe onychomycosis but for some patients, it is medically inappropriate. Additionally, for many patients, there is a strong personal preference for a non-systemic approach.24 Topical therapy would seem to be a good solution to the problem if only the efficacy rates were better. Many OTC and prescription products are available, hinting that there is no clearly effective topical choice. So what does the best evidence tell us?

   Ciclopirox 8% lacquer (Loprox, Medicis) is the best topical available in the U.S. for onychomycosis.25 Despite this, it achieves less than a 9 percent complete clearing rate and is only indicated for cases of mild to moderate severity without lunula involvement. This certainly leaves out severe, thick onychomycosis.25 In a yearlong study, the complete cure rate for terbinafine solution was no better than vehicle and nail thickness naturally impeded any improvement.26

   Since the market for an effective topical therapy for onychomycosis is large, researchers are currently studying many drugs and modalities. The most notable new topical drugs are tavaborole (AN2690, Anacor Pharmaceuticals), which belongs to the benzoxaborole class of drugs, and efinaconazole (Valeant Pharmaceuticals) and luliconazole (Topica Pharmaceuticals), which belong to the azole class of drugs.27

   In topical drug delivery, the vehicle seems to make the difference. The active ingredient in ciclopirox lacquer goes to the site of the infection in the nail bed by using an occlusive surface sealant of hair spray (Gantrez). It seals the nail plate, slowing the evaporation of water and establishing a diffusion gradient to facilitate the passage of ciclopirox through the hydrophilic nail plate to the nail bed.

   Many available topical therapies contain agents that are fungistatic in vitro but offer no evidence demonstrating penetration to the site of the infection in the nail bed. Companies often market topicals with anecdotal reports of effectiveness and illustrated with before and after images, but these agents lack controlled efficacy studies. Typically, topicals contain a tried and true antifungal agent dissolved in alcohol or vegetable oil vehicles to attempt nail plate penetration. Some commonly recommended topical antifungal solutions even lack an indication for onychomycosis but nonetheless come with a convenient brush applicator for nails.28,29

Assessing The Role Of Debridement In Managing Symptoms Of Severe Onychomycosis

To control symptoms and reduce the risks of subungual ulceration and secondary bacterial infection, clinicians can use periodic debridement to successfully manage severe onychomycosis in patients who are unable to benefit from oral therapy or unable to apply topicals. Unfortunately, debridement is unlikely to clear fungal infections.30

   Debridement techniques may vary but the goals of symptom control and risk reduction are the same. One successful method is to prepare the nail with a softening agent like diluted antimicrobial soap solution or a wetting agent. One can reduce the bulk of the nail plate with a large nail nipper and subsequently thin and smooth the nail plate with a 25,000 rpm rotary instrument. Use a coarse, fluted, pear-shaped rotary burr with firm, proximal to distal longitudinal and transverse strokes. A continuous spray of alcohol solution cools the digit and sequesters the fine nail debris. Pressure, pain and discomfort often immediately resolve.

Comments

A great article on "fungus nail" involvement with methods, drugs & outcome by my friend Dr. Ron Bodman. I also noticed over the years that there is most definitely an immune system involvement in nail fungus & C. albicans infection. As we say in WV, "it runs in the family." I have seen patients with specific toenails involved & some of their offspring have identical involvement. Some people do not have the ability to defend against the fungus organisms. They are then resistant to curative measures & tend to become reinfected after treatment.

We know fungi like a dark, warm, moist place to grow with a food source. I would like to suggest that perhaps contributing factors leading to an increase in nail & skin fungal infections over the last 20+ years may be connected to external changes in clothing & shoe gear. Over this time, we have seen a real increase in the use of artificial fibers such as nylon and polyester in socks/hosiery. These fabrics do not absorb moisture & raise the local temperature of the foot. There is no wick action with these fibers . Once again, today's shoe gear is entirely or mostly artificial uppers & lowers. These have the same characteristics. The feet are warmer, wetter, dark & there is little or no air circulation. The insoles/linings of the shoes are plastic fibers. The soles are rubber/vinyl.

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