What is the management for fungal toe infections, specifically onychomycosis?

Management of Fungal Toe Infections (Onychomycosis)

Oral terbinafine 250mg daily for 12 weeks is the first-line treatment for toenail fungal infections (onychomycosis), with mycological cure rates of 70-80%. 1

Diagnosis Confirmation

Before initiating treatment, confirm the diagnosis through:

• Potassium hydroxide (KOH) microscopic examination
• Mycological culture
• Nail biopsy in doubtful cases

This confirmation is essential as only about 50% of nail dystrophies are fungal in origin. 1

Treatment Algorithm

First-line Treatment:

• Oral terbinafine 250mg once daily for 12 weeks
  • Highest efficacy (73-94% mycological cure rate) 1
  • Superior to itraconazole (73% vs 45.8% mycological cure at 48 weeks) 2
  • Continuous dosing is more effective than pulse dosing (76.67% vs 26.67%) 3

Second-line Options:

• Oral itraconazole 200mg daily for 12 weeks

  • 45.8% mycological cure rate at 48 weeks 1
  • Consider when terbinafine is contraindicated

• Oral fluconazole 150-450mg once weekly for at least 6 months

  • Lower efficacy than terbinafine but may improve compliance due to weekly dosing 1

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

• Ciclopirox 8% nail lacquer

  • 34% mycological cure rate 1
  • Apply daily for up to 48 weeks 4
  • Requires monthly removal of unattached infected nail by a healthcare professional 4

• Efinaconazole 10% solution (50% mycological cure rate) 1

• Amorolfine 5% nail lacquer (50% efficacy in distal nail infections) 1

Special Populations

Immunocompromised Patients:

• Consider topical options when systemic therapy is contraindicated
• Terbinafine or fluconazole preferred over itraconazole due to fewer drug interactions 1

Diabetic Patients:

• Terbinafine preferred due to lower risk of drug interactions
• Topical treatments appropriate for mild-to-moderate infections where risk of drug interaction is high 1

Pediatric Patients:

• Terbinafine dosing based on weight:
  • 62.5 mg/day for children under 20 kg
  • 125 mg/day for children between 20-40 kg
  • 250 mg/day for children over 40 kg 1

Prevention of Recurrence

Recurrence occurs in 40-70% of cases. Preventive measures include:

• Maintain short, clean nails
• Dry feet thoroughly after bathing
• Wear cotton socks and change them daily
• Apply antifungal powders to shoes and feet
• Avoid sharing nail clippers
• Wear protective footwear in public areas
• Treat concomitant fungal infections promptly 1

Management of Treatment Failure

Common reasons for failure include:

• Poor compliance
• Poor drug absorption
• Immunosuppression
• Dermatophyte resistance
• Subungual dermatophytoma
• Zero nail growth 1

Options for management of treatment failure:

• Partial nail removal plus antifungal therapy
• Alternative antifungal drug
• Complete nail avulsion combined with antifungal therapy 1

Common Pitfalls to Avoid

• Not confirming diagnosis before treatment: Always obtain laboratory confirmation
• Inadequate treatment duration: Complete the full 12-week course for terbinafine
• Unrealistic expectations: Inform patients that visible improvement takes time
• Not addressing predisposing factors: Treat concomitant tinea pedis
• Concomitant use of systemic and topical antifungals: Not recommended due to potential reduced effectiveness 4