What is the treatment for a 30-year-old female with onychomycosis (fungal nail infection) presenting with yellowish nails?

Management of Yellowish Nails in a 30-Year-Old Female

Before initiating any treatment, you must obtain mycological confirmation through potassium hydroxide (KOH) preparation and fungal culture, as 50% of dystrophic nails are non-fungal despite similar clinical appearance. 1, 2

Immediate Diagnostic Steps

• Perform direct microscopy with KOH preparation and fungal culture on Sabouraud's glucose agar to confirm fungal infection before starting any antifungal therapy 2, 3
• Calcofluor white staining can enhance visualization of fungal elements if available 3
• Examine for associated findings: nail plate thickening, friable texture, onycholysis (nail separation), and subungual hyperkeratosis that suggest onychomycosis 2, 3
• Rule out non-fungal causes including psoriasis, lichen planus, trauma, bacterial infection (Green Nail Syndrome from Pseudomonas), and yellow nail syndrome, as these require different management 2, 3

First-Line Treatment for Confirmed Dermatophyte Onychomycosis

If fungal infection is confirmed, oral terbinafine is the preferred first-line treatment with superior efficacy (76% mycotic cure rate) compared to all other agents. 1, 4, 5

Oral Terbinafine Regimen

• Prescribe terbinafine 250 mg daily for 6 weeks for fingernails or 12 weeks for toenails 1, 3
• This provides the highest cure rate and shortest treatment duration compared to other systemic agents 4, 5
• Obtain baseline liver function tests and complete blood count before initiating therapy 3
• Monitor for drug-drug interactions if patient takes tricyclic antidepressants, SSRIs, atypical antipsychotics, beta blockers, or tamoxifen 4

Alternative Oral Therapy: Itraconazole

• Use itraconazole as first-line alternative, particularly if Candida species is suspected 1, 3
• Pulse therapy: 400 mg daily for 1 week per month—2 pulses (2 months) for fingernails, 3 pulses (3 months) for toenails 1, 3
• Continuous therapy: 200 mg daily for 12 weeks 1
• Achieves 63% mycotic cure rate with pulse dosing 5
• Take with food for optimal absorption; monitor liver function tests in patients with pre-existing abnormalities or receiving continuous therapy >1 month 1, 3

Topical Therapy (For Mild to Moderate Disease Without Lunula Involvement)

Topical therapy is less effective than oral agents (failure rate exceeding 60%) but can be used for mild to moderate onychomycosis with fewer adverse effects and drug interactions. 4, 5

Ciclopirox 8% Nail Lacquer

• Apply once daily (preferably at bedtime) to all affected nails, nail bed, hyponychium, and undersurface of nail plate 6
• Do not remove daily—apply over previous coat and remove with alcohol every 7 days 6
• Continue for up to 48 weeks as part of comprehensive management 6
• Achieves only 5.5-8.5% complete cure rate, making it significantly less effective than oral therapy 6, 5

Newer Topical Options

• Efinaconazole 10% solution or tavaborole 5% solution are more effective topical alternatives if available 4, 7

Essential Adjunctive Measures (Critical for Treatment Success)

Nail debridement and trimming used concurrently with pharmacologic therapy significantly improve treatment response and are mandatory components of comprehensive management. 1, 6, 4

• Have a healthcare professional trained in nail disorders remove unattached, infected nail monthly 1, 6
• Patient should file away loose nail material with emery board and trim nails weekly 6
• Apply daily topical emollients to periungual folds and nail plate to maintain hydration 2, 3
• For thick nails, apply urea-based keratolytic cream daily to reduce nail thickness 2

Prevention of Recurrence (25-50% Relapse Rate)

• Discard old footwear or treat with naphthalene mothballs in sealed plastic bag for minimum 3 days 1
• Apply antifungal powder (miconazole, clotrimazole, or tolnaftate) inside shoes and on feet regularly 1, 3
• Spray terbinafine solution into shoes periodically 1, 3
• Always wear protective footwear in public bathing facilities, gyms, and hotel rooms 1
• Wear cotton, absorbent socks and avoid occlusive footwear 1, 3
• Keep nails as short as possible and avoid sharing nail clippers with family members 1
• Examine and treat all infected family members simultaneously, as onychomycosis is contagious 1, 3

Critical Pitfalls to Avoid

• Never diagnose onychomycosis based on appearance alone—always obtain mycological confirmation before starting lengthy and potentially toxic antifungal therapy 1, 2, 3
• Do not use concomitant systemic and topical antifungal therapy, as no studies support this combination and it may reduce effectiveness 6
• Do not overlook examination of family members for fungal infections, as household transmission is common 3
• Avoid treating without addressing predisposing factors like chronic moisture exposure, trauma, and occlusive footwear 2, 3

Follow-Up and Monitoring

• Reassess at end of treatment course to confirm mycological cure with repeat KOH and culture 1
• Post-treatment assessment at 12 weeks is recommended for patients who achieve complete cure 6
• Counsel patients that despite treatment, recurrence rates range from 10-50% due to reinfection or incomplete mycological cure 4, 5, 7