What are the treatment options for onychomycosis?

Treatment Options for Onychomycosis

Terbinafine is the first-line oral treatment for onychomycosis due to its superior efficacy, fungicidal properties, and favorable cost-effectiveness profile. 1, 2

First-Line Treatments

Oral Medications

• Terbinafine is FDA-approved for onychomycosis of toenails and fingernails due to dermatophytes, with dosage of 250 mg daily for 6 weeks (fingernails) or 12 weeks (toenails) 1, 3
• Terbinafine works by inhibiting squalene epoxidase, depleting ergosterol and accumulating squalene, creating a direct fungicidal effect against dermatophytes 1, 2
• Itraconazole is an effective alternative first-line treatment, administered as 200 mg twice daily for 1 week per month (pulse therapy), with two pulses for fingernails and three for toenails 1, 4
• Itraconazole has better absorption with food and acidic pH but has contraindications including heart failure and potential hepatotoxicity 2

Topical Treatments

• Topical treatments are recommended only for superficial white onychomycosis, very early distal lateral subungual onychomycosis, or when systemic therapy is contraindicated 1, 4
• Ciclopirox 8% nail lacquer is FDA-approved for mild to moderate onychomycosis without lunula involvement, with mycological cure rates of 34% vs 10% with placebo 2, 5
• Amorolfine 5% nail lacquer is effective in approximately 50% of cases when infection is limited to the distal portion of the nail 1, 2
• Topical treatments generally have incomplete efficacy compared to systemic agents and require longer treatment courses 6

Special Populations

Diabetic Patients

• Terbinafine is the preferred treatment for diabetic patients due to lower risk of drug interactions and hypoglycemia 1, 4
• Onychomycosis is a significant predictor for foot ulcers in diabetics, making treatment particularly important in this population 1, 4

Immunosuppressed Patients

• Terbinafine and fluconazole are preferred for immunosuppressed patients due to lower risk of interactions with antiretrovirals 1, 2
• Most cases in immunosuppressed patients are due to T. rubrum 2

Pediatric Patients

• For children, pulse itraconazole therapy (5 mg/kg/day for 1 week every month) is recommended for 2 months for fingernail infection and 3 months for toenail infection 1, 4
• Terbinafine dosing for pediatric patients is weight-based: 62.5 mg/day if <20 kg, 125 mg/day for 20-40 kg, and 250 mg/day if >40 kg 1, 4

Second-Line Treatments

• Griseofulvin is now considered a third-line agent due to poor cure rates (30-40%), high relapse rates, and lengthy treatment duration (6-18 months) 1, 4
• Fluconazole, while not FDA-approved for onychomycosis in the US, is frequently used off-label with good efficacy 7

Emerging Treatments

• Photodynamic therapy has shown cure rates of 44.3% at 12 months, but evidence remains limited 1, 4
• Laser therapy, including 1064nm Nd:YAG lasers, has promising results but insufficient evidence for strong recommendations 1, 8
• New topical and oral therapies, combination approaches, and over-the-counter options are currently under investigation 8, 7

Prevention of Recurrence

• Onychomycosis has high recurrence rates (40-70%), necessitating preventive strategies 1, 2
• Prevention includes wearing protective footwear in public facilities, using absorbent and antifungal powders in shoes, keeping nails short, and avoiding sharing nail clippers 1, 2

Treatment Challenges and Considerations

• Prior to initiating treatment, appropriate nail specimens for laboratory testing (KOH preparation, fungal culture, or nail biopsy) should be obtained to confirm the diagnosis 3, 7
• Treatment failure may occur due to dense white lesions requiring mechanical removal, thick nails, severe onycholysis, slow outgrowth, and poor compliance with lengthy treatment regimens 2
• When selecting treatment, consider disease severity, infecting pathogen, medication safety, efficacy, cost, and patient factors such as age, comorbidities, and likelihood of compliance 7