INTRODUCTION
Onychomycosis is a chronic fungal infection caused by dermatophytes, yeast, or non-dermatophyte molds and is the most common nail disease, accounting for up to 50% of all nail dystrophies.1 It is a significant global public health issue, having a prevalence of 2%-26% worldwide.2–5 Onychomycosis is not just an aesthetic concern, as it may cause pain, difficulty with ambulation and performing activities of daily life, and inhibit employment and social interactions.6 A number of risk factors may contribute to both the onset and progression of onychomycosis. Chief among these is advanced age; one recent study reported prevalence of onychomycosis at 16% or higher in patients 60 years or older, compared to 8.5% in those below 60 years.7 Several comorbidities are also associated with an increased risk of onychomycosis: psoriasis,8 immunosuppression,9 cancer,10 peripheral arterial disease,11 a history of atopic disorders,12 diabetes,10,13 and obesity.14 Furthermore, familial links in susceptibility to fungal nail infections suggests a genetic component to the incidence of onychomycosis.15 An interesting disparity arises when considering the difference of onychomycosis in men and women: while males appear more likely to be afflicted with onychomycosis, females experience a greater impact on quality of life. Specifically, men are up to 3 times more likely to develop fungal nail disease than women.2 While the reasons are unknown, several hypotheses have been proposed. For example, men are more likely to have occupations requiring increased use of occlusive footwear and resulting in more frequent nail injuries.16 In addition, men may be more likely to participate in sporting activities leading to excessive perspiration thus creating opportunity for injury to the nails, and utilize communal bathing areas, thus promoting transmission of fungal elements.17–19 Furthermore, gender dependent hormone levels may result in different capacities to inhibit dermatophyte proliferation.2 In contrast to the prevalence data, women experience greater impacts on quality of life compared to males. The presence of onychomycosis was more likely to cause embarrassment in women than in men (83% vs 71%; n=258), and women rated their resulting embarrassment as “severe” more often than men (44% vs 26%; n=258).20 Women are more likely to experience pain (33.7% for women vs 26.7% in men; P<0.001) and discomfort with ambulation (43.1% of women, 25.1% of men; P<0.001).21 One 2013 study reported that women with onychomycosis had significantly lower quality-of-life scores when it came to physical functioning, pain, social functioning, and mental health scales as
