What are the treatment options for onychomycosis (nail fungus)?

Treatment Options for Onychomycosis (Nail Fungus)

Terbinafine is the first-line oral treatment for dermatophyte onychomycosis due to its superior efficacy and fungicidal properties. 1

Diagnosis Before Treatment

• Treatment should not be commenced before mycological confirmation of infection (KOH preparation, fungal culture, or nail biopsy) 1, 2
• Dermatophytes are the most common causative organisms in onychomycosis 1
• Yeasts and non-dermatophyte molds require careful interpretation as they may be secondary infections or saprophytes 1

Treatment Options Based on Pathogen

For Dermatophyte Onychomycosis:

Oral Treatments:

• Terbinafine (first-line):

  • Dosage: 250 mg daily for 6 weeks (fingernails) and 12-16 weeks (toenails) 1
  • Mechanism: Inhibits squalene epoxidase in fungal cell wall synthesis, has fungicidal properties 1
  • Advantages: Higher cure rates (70-80% for toenails, 80-90% for fingernails), lower relapse rates 1
  • Monitoring: Baseline liver function tests and complete blood count recommended 1
  • Common side effects: Headache, taste disturbance, gastrointestinal upset 1

• Itraconazole (alternative first-line):

  • Dosage options:
    • Continuous: 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
  • Best absorbed with food and acidic pH 1
  • Common side effects: Headache and gastrointestinal upset 1
  • Caution: Contraindicated in heart failure, monitor hepatic function 1

• Fluconazole (alternative):

  • Dosage: 150-450 mg weekly for 3 months (fingernails) or at least 6 months (toenails) 1
  • Useful alternative when patients cannot tolerate terbinafine or itraconazole 1

• Griseofulvin (not recommended as first-line):

  • Lower efficacy, higher relapse rates, and longer treatment duration compared to newer agents 1
  • Dosage: 500-1000 mg daily for 6-9 months (fingernails) or 12-18 months (toenails) 1

Topical Treatments:

• Amorolfine 5% nail lacquer:

  • Applied once or twice weekly for 6-12 months 1
  • Most useful for superficial and distal onychomycosis 1

• Ciclopirox 8% nail lacquer:

  • Applied daily for up to 48 weeks 1, 3
  • Requires monthly removal of unattached, infected nail by a healthcare professional 3
  • Complete cure rates are modest (5.5-8.5%) 3

For Candida Onychomycosis:

• Itraconazole (first-line):

  • Most effective agent for candidal onychomycosis 1
  • Dosage: Same as for dermatophytes (400 mg daily for 1 week per month, 2 pulses for fingernails) 1

• Fluconazole:

  • Alternative if itraconazole is contraindicated 1
  • Dosage: 50 mg daily or 300 mg weekly 1

• Topical treatments:

  • Effective for most yeast infections, particularly those associated with paronychia 1
  • Imidazole lotion alternating with antibacterial lotion is usually effective 1

For Non-dermatophyte Mold Infections:

• Itraconazole:
  • Broader antimicrobial coverage for non-dermatophyte molds 1
  • Particularly effective against Aspergillus species 1, 4
  • Clinical cure rates of 88% for single mold infections 4

Special Populations

Diabetic Patients:

• Terbinafine preferred:
  • Lower risk of drug interactions and hypoglycemia 1
  • Itraconazole is contraindicated in congestive heart failure, which is more prevalent in diabetics 1

Immunosuppressed Patients:

• Terbinafine or fluconazole preferred:
  • Lower risk of interactions with antiretrovirals compared to itraconazole 1
  • Griseofulvin is least effective in immunosuppressed patients 1

Prevention of Recurrence

• Keep nails short and avoid sharing nail clippers 1
• Wear protective footwear in public places (hotels, gyms, swimming pools) 1
• Use antifungal powders containing miconazole, clotrimazole, or tolnaftate in shoes 1
• Wear cotton, absorbent socks 1
• Consider discarding contaminated footwear or treating with naphthalene mothballs 1

Common Pitfalls and Caveats

• Treatment failure may occur due to:

  • Presence of dermatophytomas (dense white lesions beneath the nail) that require removal 1
  • Nail thickness >2mm, severe onycholysis, or slow nail growth 1
  • Poor compliance with lengthy treatment regimens 1
  • Misdiagnosis of the causative organism 1

• Recurrence rates are high (40-70%), emphasizing the importance of preventive measures 1, 5

• Follow-up should be at least 48 weeks (preferably 72 weeks) from the start of treatment to properly assess efficacy and identify relapses 1