American Academy of Family Physicians (AAFP) Journal: Published on October 2021

Onychomycosis is a chronic fungal infection of the fingernail or toenail bed leading to brittle, discolored, and thickened nails. 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.

This article provides a summary of the best available patient-oriented evidence on the diagnosis and management of this condition.

TAKE HOME MESSAGE

Confirmatory testing using potassium hydroxide preparation with direct microscopy is recommended before initiating treatment for onychomycosis.

Terbinafine has the highest effectiveness of any available therapy and should be recommended as first-line therapy for most patients without contraindications.

Topical therapy can be used to treat patients with superficial onychomycosis or early distal lateral subungual onychomycosis.

Diagnosis of Onychomycosis

A diagnosis of onychomycosis can be strongly suspected based on the typical clinical features such as nail discoloration, subungual hyperkeratosis/debris, onycholysis, and onychauxis

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.

Management of Onychomycosis

Treatment decisions should be based on severity, comorbidities, and patient preference.

Oral antifungal therapy is considered the gold standard for onychomycosis both in children and adults because of shorter courses of treatment and higher cure rates when compared with topical antifungal therapy

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.