What are the treatment options for onychomycosis (fungal infection of the nails)?

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

Systemic Treatment Options

First-Line Oral Treatments

• Terbinafine is the most effective systemic treatment with highest cure rates and is FDA-approved for onychomycosis, administered at 250 mg daily for 6 weeks for fingernails and 12 weeks for toenails 1, 2
• Terbinafine works by inhibiting squalene epoxidase, depleting ergosterol and accumulating squalene, which is directly fungicidal against dermatophytes 1
• Side effects include headache, taste disturbance, gastrointestinal upset, and rarely can aggravate psoriasis or cause lupus-like syndrome 1
• Contraindicated in hepatic impairment; monitor for drug interactions with tricyclic antidepressants, SSRIs, beta blockers, and tamoxifen 1, 3

Alternative Oral Treatments

• Itraconazole is an effective alternative, administered as 200 mg twice daily for 1 week per month (pulse therapy), with two pulses for fingernails and three for toenails 1
• Itraconazole has better absorption with food and acidic pH but has more drug interactions and is contraindicated in heart failure 1
• Itraconazole is particularly effective against Candida species, making it a good choice for yeast infections of the nail 4, 1
• Griseofulvin is now considered a third-line agent due to poor cure rates (30-40%), high relapse rates, and lengthy treatment duration (6-18 months) 4, 1

Topical Treatment Options

• Topical therapy should only be used for superficial white onychomycosis (SWO), very early distal lateral subungual onychomycosis (DLSO), or when systemic therapy is contraindicated 4
• Amorolfine 5% nail lacquer is effective in approximately 50% of cases when infection is limited to the distal portion of the nail 4, 1
• Ciclopirox 8% nail lacquer has mycological cure rates of 34% (vs 10% with placebo) and requires monthly removal of unattached, infected nail by a healthcare professional 1, 5
• Newer topical options include efinaconazole and tavaborole, which have shown improved nail penetration compared to older topical agents 6, 3

Special Populations

Diabetic Patients

• Terbinafine is the preferred treatment for diabetic patients due to lower risk of drug interactions and hypoglycemia 4, 1
• Onychomycosis is a significant predictor for foot ulcers in diabetics, making treatment particularly important in this population 4

Immunosuppressed Patients

• Most cases in immunosuppressed patients are due to T. rubrum 4
• Terbinafine and fluconazole are preferred due to lower risk of interactions with antiretrovirals 4, 1

Pediatric Patients

• Pulse itraconazole therapy (5 mg/kg/day for 1 week every month) is recommended for 2 months for fingernail infection and 3 months for toenail infection 4
• Terbinafine is recommended for children based on weight: 62.5 mg/day if <20 kg, 125 mg/day for 20-40 kg, and 250 mg/day if >40 kg 4
• Fluconazole can be used at 3-6 mg/kg once weekly for 12-16 weeks for fingernail infection and 18-26 weeks for toenail infection 4

Emerging Treatments

• Newer azoles such as posaconazole, fosravuconazole, and oteseconazole show promising results but are not yet FDA-approved for onychomycosis 7
• Laser and light therapies (including 1064-nm Nd:YAG lasers) show some promise but currently lack sufficient evidence for strong recommendations 4, 6
• Photodynamic therapy has shown cure rates of 44.3% at 12 months, but evidence remains limited 4

Prevention of Recurrence

• Onychomycosis has high recurrence rates (40-70%), necessitating preventive strategies 4, 1
• Prevention includes wearing protective footwear in public facilities, using absorbent and antifungal powders in shoes, keeping nails short, and avoiding sharing nail clippers 4
• Consider discarding contaminated footwear or treating with naphthalene mothballs in a sealed plastic bag for 3 days 4

Treatment Challenges

• Treatment failure may occur due to dermatophytomas (dense white lesions requiring mechanical removal), thick nails (>2 mm), severe onycholysis, and slow nail outgrowth 4
• Compliance with lengthy treatment regimens is a common challenge, particularly with topical therapies 1, 8
• Confirmation of diagnosis through appropriate testing (KOH preparation, fungal culture, or nail biopsy) is essential before initiating treatment 2, 8