What are the treatment options for nail infections, particularly those caused by fungi?

Treatment Options for Nail Infections (Onychomycosis)

Systemic therapy is almost always more successful than topical treatment for nail fungal infections, with terbinafine being the first-line treatment for dermatophyte infections due to its superior efficacy and safety profile. 1

Diagnosis Before Treatment

Before initiating treatment, proper diagnosis is essential:

• Direct microscopy and fungal culture should be performed to confirm infection
• Most common cause of treatment failure is incorrect diagnosis made on clinical grounds alone 2
• Non-fungal causes of nail dystrophy (like psoriasis) should be ruled out

Treatment Algorithm

First-Line Therapy for Dermatophyte Infections (most common):

1. Oral Terbinafine:
   • Dosage: 250 mg daily
   • Duration: 6 weeks for fingernails, 12-16 weeks for toenails
   • Efficacy: 70-80% mycological cure rate 1
   • Advantages: Fungicidal action, high cure rates, good compliance 2
   • Monitoring: Baseline liver function tests recommended 1

Alternative Systemic Options:

1. Oral Itraconazole:

   • Preferred for Candida infections
   • Dosage options:
     • Continuous: 200 mg daily for 12 weeks
     • Pulse therapy: 400 mg daily for 1 week per month for 3-4 months
   • Less effective than terbinafine for dermatophytes 2, 1
   • More drug interactions than terbinafine 2

2. Oral Fluconazole:

   • Dosage: 150-450 mg once weekly
   • Duration: 3 months for fingernails, at least 6 months for toenails
   • Better tolerated but less effective than terbinafine or itraconazole 1

3. Griseofulvin (not recommended as first-line):

   • Poor cure rates (only about 30%)
   • Lengthy treatment necessary
   • High relapse rates 2, 3

Topical Therapy Options (for mild cases or when oral therapy is contraindicated):

1. Amorolfine 5% nail lacquer:

   • Application: Once or twice weekly for 6-12 months
   • Efficacy: ~50% mycological cure rate 2, 1
   • First-line topical treatment for mild to moderate cases

2. Ciclopirox 8% lacquer:

   • Application: Once daily for up to 48 weeks
   • Efficacy: 34% mycological cure rate 1

3. Tioconazole 28% solution:

   • Application: Twice daily
   • Efficacy: 22% mycological and clinical cure rate 1

Special Considerations

Based on Infecting Organism:

• Dermatophytes: Terbinafine is most effective 1
• Candida infections: Itraconazole or fluconazole preferred 1, 4
• Non-dermatophyte molds: Treatment should be guided by susceptibility testing 1

For Special Populations:

• Diabetics: Consider topical treatments for mild infections; terbinafine preferred for systemic therapy due to fewer drug interactions 1
• Immunosuppressed patients: Consider drug interactions carefully; terbinafine or fluconazole may be preferred over itraconazole 1
• Pediatric patients: Terbinafine dosing based on weight 1

Follow-up and Monitoring

• Re-evaluation 3-6 months after starting treatment
• Continue monitoring for at least 48 weeks from treatment initiation 1
• Clinical improvement may lag behind mycological cure

Common Pitfalls and Caveats

1. Misdiagnosis: Most common cause of treatment failure is incorrect diagnosis 2
2. Inadequate treatment duration: Complete nail regrowth takes time
3. Drug interactions: Particularly with itraconazole 2
4. Liver toxicity: Monitor liver function with oral antifungals, especially terbinafine 5
5. Unrealistic expectations: Clinical improvement often lags behind mycological cure 2
6. Treating without confirmation: Always confirm diagnosis with microscopy/culture before treatment 2

Prevention of Recurrence

• Keep nails short and clean
• Wear breathable footwear
• Use antifungal powders in shoes
• Wear cotton, absorbent socks
• Avoid sharing nail clippers or other personal items
• Treat any concomitant fungal infections (like athlete's foot) 1