What is the best treatment for onychomycosis (nail fungus)?

Treatment of Onychomycosis (Nail Fungus)

Oral terbinafine is the most effective first-line treatment for onychomycosis, with superior cure rates compared to other therapies. 1

Treatment Selection Algorithm

First-Line Treatment

• Oral terbinafine (250 mg daily) is recommended as first-line therapy for moderate to severe onychomycosis caused by dermatophytes 1, 2
  • Treatment duration: 6 weeks for fingernails, 12-16 weeks for toenails 1
  • Highest mycological cure rates (70-80% for toenails, 80-90% for fingernails) 1
  • Fungicidal action provides better long-term outcomes with lower relapse rates compared to itraconazole (23% vs 53% relapse) 1

Alternative Systemic Treatments

• Itraconazole (200 mg daily continuous or 400 mg pulse therapy for 1 week per month) is the second-best alternative when terbinafine is contraindicated 1

  • Pulse therapy: 2 pulses for fingernails, 3 pulses for toenails 1
  • Preferred for Candida onychomycosis 1

• Fluconazole (450 mg weekly) can be used when other systemic options are not tolerated 1

  • Less effective than terbinafine or itraconazole but better compliance with weekly dosing 1
  • Treatment duration: 3 months for fingernails, 6+ months for toenails 1

Topical Treatments

Indicated for:

• Mild to moderate disease (< 80% nail involvement)
• No lunula involvement
• When systemic antifungals are contraindicated 1

Options include:

• Amorolfine 5% lacquer: Applied once or twice weekly for 6-12 months, ~50% efficacy 1
• Ciclopirox 8% lacquer: Applied daily for up to 48 weeks, 34% mycological cure rate 1, 3
• Efinaconazole 10%: Once daily application, ~50% mycological cure rate 1

Special Populations

Pediatric Patients

• Prevalence < 0.5% in children 1
• Terbinafine is recommended based on weight:
  • 62.5 mg/day if < 20 kg
  • 125 mg/day for 20-40 kg
  • 250 mg/day if > 40 kg 1
• Itraconazole pulse therapy (5 mg/kg/day for 1 week monthly) is an alternative 1
• Treatment duration: 6 weeks for fingernails, 12 weeks for toenails 1

Candida Onychomycosis

• Itraconazole is most effective for Candida nail infections 1
• Same dosage as for dermatophytes: 400 mg daily for 1 week per month, 2 pulses for fingernails 1

Treatment Failure Management

Common causes of treatment failure include:

• Poor compliance
• Poor drug absorption
• Immunosuppression
• Dermatophyte resistance
• Subungual dermatophytoma preventing drug penetration 1

Management options:

• Switch to alternative antifungal agent
• Partial nail removal combined with antifungal therapy 1
• Consider combination therapy (topical + systemic) for synergistic effect 1

Prevention of Recurrence

• Recurrence rates are high (20-30%) even after successful treatment 1, 4
• Preventive measures include:
  • Avoiding walking barefoot in public places 4
  • Disinfecting shoes and socks 4
  • Treating concurrent tinea pedis 5
  • Consider prophylactic use of amorolfine 1

Important Caveats

• Always confirm diagnosis with laboratory testing (KOH preparation, fungal culture, or nail biopsy) before initiating treatment 1, 2
• Monitor for drug-drug interactions, especially with terbinafine and medications like tricyclic antidepressants, SSRIs, beta blockers 4
• Clinical improvement may not correlate with mycological cure, which is often 30% lower than clinical improvement rates 1
• Treatment should be continued for the full recommended duration even if visual improvement occurs early 4, 6