Onychomycosis in the Elderly

Abstract

The prevalence of onychomycosis is nearly 20% in patients aged >60 years. In North America, 90% of toenail onychomycosis is caused by dermatophytes (Trichophyton species). Distal-lateral subungual onychomycosis is the most common clinical presentation. The potassium hydroxide test is the most cost-effective diagnostic method. Although nail clipping for histology using periodic acid-Schiff stain is more sensitive, it is much more expensive. Elderly patients have specific risk factors for poor response to therapy for onychomycosis, including frequent nail dystrophy, slow growth of nails and increased prevalence of peripheral vascular disease and diabetes mellitus. Elderly people with diabetes should be treated for onychomycosis to prevent secondary bacterial infections and subsequent complications. Terbinafine is the drug of choice for dermatophyte onychomycosis, with greater mycological cure rates, less serious and fewer drug interactions, and a lower cost than continuous itraconazole therapy. Adjunct debridement may improve the clinical and complete cure rates compared with terbinafine alone. Common adverse effects of terbinafine in the elderly include nausea, sinusitis, arthralgia and hypercholesterolaemia. For onychomycosis caused by Candida or nondermatophyte moulds, there is no superior systemic therapy. In general, topical nail lacquers, amorolfine and ciclopirox are not practical for elderly patients because of the recommended frequency of application, periodic routine debridement of affected nails and long duration of therapy. However, nail lacquers may be a good option as monotherapy for patients with superficial white onychomycosis or in combination with systemic antifungal therapy for patients with predisposing factors for poor response or recurrence.