What are the treatment options for onychomycosis?

Treatment Options for Onychomycosis

Terbinafine is the first-line oral treatment for onychomycosis due to its superior efficacy, fungicidal properties, and favorable cost-effectiveness profile. 1, 2

First-Line Treatments

Oral Therapy

• Terbinafine is indicated for the treatment of onychomycosis of the toenail or fingernail due to dermatophytes (tinea unguium) 3
• Dosage: 250 mg daily for 6 weeks for fingernails or 12 weeks for toenails 2
• Mechanism: Inhibits squalene epoxidase, depleting ergosterol and accumulating squalene, which is directly fungicidal against dermatophytes 2
• Side effects: Headache, taste disturbance, gastrointestinal upset; can aggravate psoriasis and cause lupus-like syndrome 2
• Contraindication: Hepatic impairment 2

Alternative First-Line Treatment

• Itraconazole: 200 mg twice daily for 1 week per month (pulse therapy), with two pulses for fingernails and three for toenails 1, 2
• Better absorption with food and acidic pH 2
• Contraindications: Heart failure; potential hepatotoxicity 2

Topical Treatments

• Recommended only for:

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

• Options include:

  • Amorolfine 5% nail lacquer: Effective in approximately 50% of cases when infection is limited to the distal portion of the nail 1, 2
  • Ciclopirox 8% nail lacquer: Indicated as topical treatment in immunocompetent patients with mild to moderate onychomycosis without lunula involvement 4
  • Requires monthly removal of unattached, infected nail by a healthcare professional 4

Special Populations

Diabetic Patients

• Terbinafine is preferred due to lower risk of drug interactions and hypoglycemia 1, 2
• Onychomycosis is a significant predictor for foot ulcers in diabetics, making treatment particularly important 1, 2

Immunosuppressed Patients

• Most cases are due to T. rubrum 2
• Terbinafine and fluconazole are preferred due to lower risk of interactions with antiretrovirals 1, 2

Pediatric Patients

• Pulse itraconazole therapy (5 mg/kg/day for 1 week every month) for 2 months for fingernail infection and 3 months for toenail infection 1
• Terbinafine dosing based on weight:
  • 62.5 mg/day if <20 kg
  • 125 mg/day for 20-40 kg
  • 250 mg/day if >40 kg 1

Second-Line Treatments

• Griseofulvin: Least effective oral agent with mycological cure rates of only 30-40% 2, 5
• Only indicated when other agents are unavailable or contraindicated 2
• Requires longer treatment duration: 6-9 months for fingernails and 12-18 months for toenails 2
• Not effective against Candida species or nondermatophyte molds 5

Treatment Selection Based on Pathogen

• For dermatophyte infections: Terbinafine produces the best results 6, 7
• For Candida and nondermatophyte infections: Azoles (mainly itraconazole) are recommended 6

Emerging Treatments

• Photodynamic therapy: Shown cure rates of 44.3% at 12 months, but evidence remains limited 1
• Laser therapy (including 1064nm Nd:YAG lasers): Promising results but insufficient evidence for strong recommendations 8, 9

Prevention of Recurrence

• Onychomycosis has high recurrence rates (40-70%) 1, 2
• Preventive strategies:
  • Wearing protective footwear in public facilities
  • Using absorbent and antifungal powders in shoes
  • Keeping nails short
  • Avoiding sharing nail clippers 1, 2

Treatment Challenges

• Factors contributing to treatment failure:
  • Dense white lesions (dermatophytomas) requiring mechanical removal
  • Thick nails (>2 mm)
  • Severe onycholysis
  • Slow nail outgrowth 2
• Prior to initiating treatment, appropriate nail specimens for laboratory testing (KOH preparation, fungal culture, or nail biopsy) should be obtained to confirm the diagnosis 3, 7