What is the treatment for onychomycosis (toe fungus)?

Treatment of Onychomycosis (Toe Fungus)

Terbinafine is the first-line treatment for dermatophyte onychomycosis, with itraconazole as the next best alternative. 1

Diagnosis

Before initiating treatment, proper diagnosis is essential:

• Mycological confirmation through microscopy and culture is required before starting treatment 1
• Samples should be collected from the most proximal part of the infection, as fungal elements may be sparse 1
• Direct microscopy and culture should be performed by experienced laboratories to avoid misdiagnosis 1

Treatment Options

Systemic Therapy (First-line)

For most cases of onychomycosis, systemic therapy is recommended as it is significantly more effective than topical treatments 1.

Terbinafine

• First-line treatment for dermatophyte onychomycosis 1
• Dosage: 250 mg daily for 6 weeks (fingernails) or 12-16 weeks (toenails) 1
• Advantages: Fungicidal action, higher cure rates (70-80% for toenails, 80-90% for fingernails) 1, 2
• Monitoring: Baseline liver function tests and complete blood count recommended 1
• Contraindications: Hepatic impairment, renal impairment 1
• Side effects: Headache, taste disturbance, gastrointestinal upset; can aggravate psoriasis 1

Itraconazole

• Second-line treatment for dermatophyte onychomycosis 1
• Dosage options:
  • Continuous therapy: 200 mg daily for 12 weeks 1
  • Pulse therapy: 400 mg daily for 1 week per month (2 pulses for fingernails, 3 pulses for toenails) 1
• First-line for Candida onychomycosis 1
• Monitoring: Liver function tests recommended with pre-existing abnormalities or continuous therapy 1
• Contraindications: Heart failure, hepatotoxicity 1
• Side effects: Headache, gastrointestinal upset 1

Fluconazole (Alternative)

• May be used when patients cannot tolerate terbinafine or itraconazole 1, 2
• Dosage: 150-450 mg weekly for 3 months (fingernails) or at least 6 months (toenails) 1
• Not licensed for onychomycosis in some countries 1

Topical Therapy

Topical treatment should only be used in specific situations:

• Superficial white onychomycosis (SWO) 1
• Very early distal lateral subungual onychomycosis (DLSO) 1
• When systemic therapy is contraindicated 1

Ciclopirox 8% Nail Lacquer

• Indicated for mild to moderate onychomycosis without lunula involvement 3
• Requires monthly removal of unattached, infected nail by a healthcare professional 3
• Should be used as part of a comprehensive management program 3
• Limited efficacy when used alone (5.5-8.5% complete cure rate) 3

Amorolfine Nail Lacquer

• Effective in approximately 50% of cases with distal infection 1

Special Considerations

Treatment Failure

Common causes of treatment failure include:

• Incorrect diagnosis 1
• Poor compliance 1
• Subungual dermatophytoma (dense white lesion beneath the nail) 1
• Nail thickness >2mm, severe onycholysis 1

In cases of treatment failure:

• Consider alternative drug or nail removal combined with further therapy 1
• Partial nail removal may be necessary for subungual dermatophytoma 1

Prevention of Recurrence

• Keep nails short 1
• Wear protective footwear in public bathing facilities 1
• Use antifungal powders in shoes and on feet 1
• Wear cotton, absorbent socks 1
• Treat all infected family members simultaneously 1
• Consider disinfecting or discarding contaminated footwear 1

Treatment Based on Causative Organism

• Dermatophytes (most common): Terbinafine preferred over itraconazole 1, 4
• Yeasts (e.g., Candida): Itraconazole is most effective; fluconazole is an alternative 1, 4
• Non-dermatophyte molds: Treatment should be based on identification and susceptibility testing 4

Conclusion

Onychomycosis requires proper diagnosis and appropriate treatment selection based on the extent of infection, causative organism, and patient factors. Systemic therapy with terbinafine or itraconazole provides the highest cure rates, while topical treatments are reserved for limited cases or as adjunctive therapy.