INTRODUCTION
Onychomycosis refers to a fungal infection affecting the
nail plate or the nail bed of the toenails or fingernails.1
It is generally caused by dermatophytes and less frequently
by non-dermatophyte molds and yeasts.2 The term
dermatophyte refers specifically to fungi related to the genera
Trichophyton, Epidermophyton, and Microsporidium, which
cause an infection of the skin, hair and nails due to their ability
to obtain nutrients from keratinized material.3 They are usually
restricted to the non-living cornified layer of the epidermis because
of their inability to penetrate viable immunocompetent
tissue. However, any component of the nail may be involved,
including the nail matrix, nail bed or nail plate.
Onychomycosis is a medical condition with aesthetic side
effects for many patients.4 While it is not a life threatening condition,
it may lead to serious morbidity, including secondary
bacterial infections.2,5 Furthermore, onychomycosis can cause
pain, discomfort and may produce serious physical and occupational
limitations. The psychosocial and emotional effects are
widespread and may have an impact on quality of life.
Approximately 34% of diabetics have onychomycosis.2 Diabetics
are at increased risk to develop complications secondary to
onychomycosis.5,6,7 Dermatophyte infected nails can form thick,
jagged edges that can injure the surrounding skin creating foot
ulcers.5,6,8 In diabetics with associated sensory neuropathy ulcerations
can go undetected precipitating secondary bacterial
complications that can be life threatening (sepsis) or require
amputation of the lower extremities. Onychomycosis results in
a three-fold increase in relative risk for developing gangrene in
diabetic patients,5 creating a treatment imperative.
There are numerous risk factors associated with onychomycosis,
including age, family history, male gender, and diabetes
(Table 1). Adults are most commonly affected by onychomycosis
secondary to slower nail growth. Some individuals are
genetically predisposed to onychomycosis.5 The toenails are
affected more often than the fingernails, likely due to slower
nail growth, increased exposure to organisms and an increased
prevalence of injury.5 Additionally, athlete’s foot often precedes
toenail infection. The most common fungal infections of the nail