What is the treatment for fungal nail infection?

Treatment for Fungal Nail Infection (Onychomycosis)

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

Diagnosis

• Proper diagnosis through laboratory confirmation is essential before starting treatment, as 50% of nail dystrophy cases are non-fungal in origin 2
• Diagnostic methods include:
  • Direct microscopy with potassium hydroxide (20% KOH) to visualize fungal elements 2
  • Culture on Sabouraud's glucose agar to identify the causative organism 2
  • Samples should be collected from the most proximal part of the infection, as dermatophyte onychomycosis primarily affects the nail bed 2

Treatment Options

Systemic Therapy (First-Line)

• Terbinafine (250 mg daily) is the most effective treatment for dermatophyte onychomycosis:

  • 6 weeks for fingernail infections 3
  • 12 weeks for toenail infections 3
  • Works by inhibiting squalene epoxidase, creating both fungistatic and fungicidal effects 2
  • Achieves cure rates of 80-90% for fingernails and 70-80% for toenails 2

• Itraconazole (alternative when terbinafine is contraindicated):

  • Pulse therapy: 400 mg daily for 1 week per month 2
  • Two pulses for fingernail infections, three pulses for toenail infections 2
  • Most effective agent for Candida nail infections 2

Topical Therapy (Limited Cases)

• Topical treatment should only be used for:

  • Superficial white onychomycosis (SWO) 2
  • Very early distal lateral subungual onychomycosis (DLSO) 2
  • When systemic therapy is contraindicated 2

• Ciclopirox 8% nail lacquer:

  • Applied daily as part of a comprehensive management program 4
  • Requires monthly removal of unattached, infected nails by a healthcare professional 4
  • Achieves complete cure in approximately 5.5-8.5% of cases 4

Management Approach

1. Confirm diagnosis with laboratory testing before starting treatment 2
2. Assess infection severity:
   • If mild or limited to distal nail: consider topical therapy 5
   • If moderate to severe or involving >50% of nail plate: use oral therapy 6
3. Select appropriate treatment:
   • For dermatophytes (most common): terbinafine is first choice 2
   • For Candida infections: itraconazole is preferred 2
4. Monitor for treatment success:
   • Complete nail growth takes approximately 12 months for toenails and 6 months for fingernails 2
   • Treatment success should be evaluated after this period 2

Special Considerations

• Treatment failure is often due to:
  • Incorrect diagnosis 2
  • Poor compliance 2
  • Subungual dermatophytoma preventing drug penetration 2
• Diabetic patients should prioritize treatment as onychomycosis increases risk of foot ulcers 1
• Side effects to monitor with oral therapy:
  • Terbinafine: liver problems, taste disturbances, skin reactions 3
  • Itraconazole: drug interactions, especially with medications for heart conditions 3

Prevention of Recurrence

• Onychomycosis has high recurrence rates (40-70%) 1
• Preventive measures include:
  • Wearing protective footwear in public facilities 1
  • Using antifungal powders in shoes 1
  • Keeping nails short 1
  • Avoiding sharing nail clippers 1

Treatment Algorithm

1. Confirm fungal infection through laboratory testing 2
2. Identify causative organism (dermatophyte, Candida, or mold) 2
3. Assess extent of infection:
   • <50% of nail involvement: consider topical therapy 6

   • 50% of nail involvement: use oral therapy 6

4. Select treatment based on organism:
   • Dermatophytes: terbinafine (first choice) or itraconazole 2
   • Candida: itraconazole 2
5. Treat for appropriate duration:
   • Fingernails: 6 weeks (terbinafine) or 2 pulse cycles (itraconazole) 3, 2
   • Toenails: 12 weeks (terbinafine) or 3 pulse cycles (itraconazole) 3, 2
6. Evaluate treatment success after complete nail growth (6-12 months) 2