What is the preferred treatment for Candida albicans nail infection (onychomycosis) in an otherwise healthy adult?

Treatment of Candida Albicans Nail Infection

For Candida albicans onychomycosis with nail plate invasion, itraconazole is the first-line systemic treatment, administered as pulse therapy at 400 mg daily for 1 week per month for 2 months (fingernails) or 3-4 months (toenails). 1

Initial Assessment and Diagnosis

• Always obtain mycological confirmation (microscopy and culture) before starting systemic antifungal therapy, as only approximately 50% of nail dystrophies are actually fungal infections 2
• Distinguish between Candida paronychia (infection around the nail fold) versus true Candida onychomycosis (invasion of the nail plate itself), as treatment approaches differ significantly 1, 3
• Approximately 25% of paronychia cases develop secondary Candida superinfection 3

Treatment Algorithm Based on Disease Pattern

For Candida Paronychia (Without Nail Plate Invasion)

Topical therapy is first-line for Candida-associated paronychia:

• Apply topical imidazole lotions (clotrimazole or miconazole) to the affected nail folds 1, 3
• Alternate with antibacterial lotions if bacterial co-infection is suspected 1
• Continue application until cuticle integrity is restored, which may take several months 1
• Use broad-spectrum, colorless, non-sensitizing antiseptics that can wash beneath the cuticle to sterilize the subcuticular space 1

For Candida Onychomycosis (With Nail Plate Invasion)

Itraconazole is markedly superior to terbinafine for Candida nail infections, achieving 92% cure rates versus only 40% with terbinafine 2

Itraconazole Pulse Therapy Regimen:

• Fingernails: 400 mg daily (200 mg twice daily) for 1 week per month × 2 pulses (total 2 months) 1, 2
• Toenails: 400 mg daily for 1 week per month × 3-4 pulses (total 3-4 months) 1, 2
• Must be taken with food and acidic beverages to optimize absorption 2
• Clinical studies demonstrate 90.6% mycological cure for toe onychomycosis and 100% for finger onychomycosis caused by Candida species 4

Pre-Treatment Requirements:

• Obtain baseline liver function tests (LFTs) before initiating therapy 2
• Monitor hepatic function tests if continuous therapy exceeds 1 month or if patient has pre-existing liver abnormalities 2
• Review all concurrent medications for potential drug interactions 2

Critical Drug Interactions and Contraindications:

Itraconazole is contraindicated with:

• Terfenadine, astemizole, sertindole, midazolam, and cisapride (enhanced toxicity) 2
• Heart failure (negative inotropic effects) 2
• Pregnancy 2

Itraconazole increases levels of:

• Warfarin, digoxin, ciclosporin, and simvastatin (increased myopathy risk) 1, 2
• Statins generally—consider temporary dose adjustment or monitoring 2

Alternative Systemic Options

When Itraconazole Cannot Be Used:

Fluconazole is the preferred alternative:

• Dosing: 150-450 mg once weekly for minimum 4 weeks (fingernails) or 12 weeks (toenails) 3, 2
• Has fewer drug interactions with statins compared to itraconazole 2
• Requires baseline LFTs and CBC, with monitoring during prolonged therapy 2

Why Terbinafine Should Be Avoided:

• Terbinafine has limited and unpredictable activity against Candida species 3
• Cure rates are only 40% for Candida infections versus 92% with itraconazole 2
• Should not be used as first-line for confirmed Candida onychomycosis 3

Adjunctive Topical Therapy

Combining systemic and topical treatments enhances cure rates:

• Amorolfine 5% lacquer applied once or twice weekly for 6-12 months 2
• Ciclopirox 8% lacquer applied once daily for up to 48 weeks 2
• Combination therapy provides wider antifungal spectrum, improved fungicidal activity, and suppression of resistant mutants 2

Monitoring and Follow-Up

• Monitor patients for at least 48 weeks from treatment initiation to detect potential relapse 2
• Itraconazole persists in nails at therapeutic concentrations for months after stopping therapy (detectable up to 27 weeks post-treatment) 5, 6
• End-of-therapy culture is recommended to confirm mycological clearance 2
• Mycological cure rates typically exceed clinical cure rates by approximately 30% 2

Common Pitfalls to Avoid

• Never start systemic antifungal therapy without mycological confirmation—many nail dystrophies are non-fungal 2
• Do not use terbinafine for Candida onychomycosis—it is significantly inferior to itraconazole 3, 2
• Do not forget to screen for drug interactions, especially in elderly patients on multiple medications 2
• Ensure adequate treatment duration—premature discontinuation leads to treatment failure 1
• Recognize that yeasts are often secondary colonizers in previously damaged nails; address underlying nail trauma or chronic paronychia 1