Onychomycosis: Rapid Evidence Review

Onychomycosis is a chronic fungal infection of the fingernail or toenail bed leading to brittle, discolored, and thickened nails. Onychomycosis is not just a cosmetic problem. Untreated onychomycosis can cause pain, discomfort, and physical impairment, negatively impacting quality of life. Onychomycosis should be suspected in patients with discolored nails, nail plate thickening, nail separation, and foul-smelling nails. Accurate diagnosis is important before initiating treatment because therapy is lengthy and can cause adverse effects. A potassium hydroxide preparation with confirmatory fungal culture, periodic acid-Schiff stain, or polymerase chain reaction is the preferred diagnostic approach if confirmative testing is cost prohibitive or not available. Treatment decisions should be based on severity, comorbidities, and patient preference. Oral terbinafine is preferred over topical therapy because of better effectiveness and shorter treatment duration. Patients taking terbinafine in combination with tricyclic antidepressants, selective serotonin reuptake inhibitors, atypical antipsychotics, beta blockers, or tamoxifen should be monitored for drug-drug interactions. Topical therapy, including ciclopirox 8%, efinaconazole 10%, and tavaborole 5%, is less effective than oral agents but can be used to treat mild to moderate onychomycosis, with fewer adverse effects and drug-drug interactions. Nail trimming and debridement used concurrently with pharmacologic therapy improve treatment response. Although photodynamic and plasma therapies are newer treatment options that have been explored for the treatment of onychomycosis, larger randomized trials are needed. Preventive measures such as avoiding walking barefoot in public places and disinfecting shoes and socks are thought to reduce the 25% relapse rate.