The prevalence of onychomycosis in diabetic patients ranges from 26% to 33%. Compared to age- and sex-matched nondiabetics, patients with diabetes have been shown to be 2.8 times more likely to have onychomycosis infections. Most of the infections are distal/lateral subungual onychomycosis caused by dermatophytes. Moreover, the development of onychomycosis in diabetic patients has been found to be highly correlated with increasing age and male gender. In fact, male diabetics are three times more likely than female diabetics to be infected. (Gupta et al, 1998; Rich, 1996; Elewski, 1997)

Onychomycosis often results from tinea pedis, which can permit a portal of entry for secondary bacterial infections. Onychomycosis can also contribute to more severe foot problems. For example, the thick mycotic nail can place pressure on the nail bed, causing nail bed erosions. Sharp mycotic nails can ulcerate adjacent perionychium skin. Moreover, the ulcerations often go unrecognized by diabetic patients because of decreased sensation, and can create a portal of infection leading to cellulitis or necrosis. Impaired wound healing may result in increased morbidity and even possible amputation. That's why it's so important to treat fungal nail infections early in diabetic patients. (Levy, 1997; Rich, 1996)

Onychomycosis is more prevalent in patients whose immune systems have been compromised by AIDS/HIV infection, organ or bone marrow transplantation, cancer chemotherapy, or long-term corticosteroid therapy. (Levy, 1997)

In HIV-infected individuals, the prevalence of onychomycosis ranges from 11% to 67%. Indeed, it is one of the earliest fungal infections to emerge in this patient group. The infection often starts as a proximal white subungual onychomycosis in HIV-infected individuals and can quickly spread to other nails of the fingers and toes. Left untreated, onychomycosis could lead to systemic infection to which the immunocompromised patient cannot respond. (Levy, 1997)

The prevalence of onychomycosis in people over age 70 is nearly 50%, compared to 13% of the U.S. population as a whole, and increases with increasing age. Reduced skeletal flexibility and joint mobility in the elderly reduces their ability to detect early signs of foot and toenail infections. Consequently, onychomycosis is likely to progress to an advanced stage of nail destruction before the infection is first detected. (Levy, 1997)

In the elderly, onychomycosis can exacerbate existing foot problems and decrease a patient's mobility and independence. Dystrophic or thickened nails can interfere with nail function, cause pain when wearing shoes, and make nail trimming difficult. (Levy, 1997)