What are the treatments for splitting fingernails?

Treatment of Splitting Fingernails

For idiopathic splitting fingernails (onychoschizia), oral biotin 1 mg/day combined with pyridoxine 100 mg/day for 3 months is the most effective treatment, achieving complete resolution in approximately 70% of patients. 1

Initial Assessment and Differential Diagnosis

Before initiating treatment, determine whether the nail splitting is primary (idiopathic) or secondary to an underlying condition:

• Rule out fungal infection (onychomycosis): Look for nail thickening, discoloration, subungual hyperkeratosis, and onycholysis—if present, obtain fungal culture or KOH preparation 2
• Exclude inflammatory conditions: Psoriasis presents with nail pitting, oil spots (salmon patches), and onycholysis; lichen planus causes nail matrix involvement with longitudinal ridging 2
• Assess for systemic disease: Nutritional deficiencies, thyroid disorders, and chronic systemic conditions can cause secondary nail brittleness 3, 4
• Evaluate environmental factors: Chronic water exposure, harsh chemicals, and repetitive trauma progressively dehydrate the nail plate 4

Treatment Algorithm for Idiopathic Onychoschizia

First-Line Treatment: Oral Supplementation

Combined oral biotin and pyridoxine is superior to either agent alone:

• Biotin 1 mg/day PLUS pyridoxine 100 mg/day for 3 months achieves complete response (>90% improvement) in 69.6% of patients, compared to only 10-11% with either agent alone 1
• Continue treatment for minimum 3 months, with assessment at 6-9 months to allow for complete nail plate replacement 1
• No adverse events reported with this combination 1
• If combination therapy unavailable, biotin alone (typically 2.5 mg/day) has historical support, though less robust evidence 3, 4

Adjunctive Topical Therapy

Add topical biomineral formulations to enhance nail hardness and reduce splitting:

• Topical biomineral products improve nail hardness by 40-50% after 3 months and reduce nail roughness by 12-18% 5
• Apply daily to affected nails; can be used alone or combined with oral supplementation 5
• Topical moisturizers and protective lacquers provide mechanical protection and reduce water loss 3, 4

Supportive Measures

Implement protective strategies to prevent further damage:

• Keep nails trimmed short and file edges smooth to prevent propagation of splits 2
• Minimize water exposure and use protective gloves for wet work 4
• Avoid harsh nail products, acetone-based removers, and aggressive manicuring 4
• Apply emollients or urea-based creams after water exposure to maintain hydration 2

Treatment of Secondary Causes

If Onychomycosis is Confirmed

Oral antifungals are first-line for dermatophyte nail infections:

• Terbinafine 250 mg daily for 6 weeks (fingernails) or 12-16 weeks (toenails) is preferred over itraconazole 2
• Itraconazole 200 mg daily for 12 weeks continuously, or pulse therapy 400 mg daily for 1 week per month (2 pulses for fingernails) 2
• Baseline liver function tests and complete blood count required before starting systemic therapy 2
• Topical therapy alone (amorolfine 5% lacquer 1-2 times weekly or ciclopirox 8% lacquer daily) only for superficial white onychomycosis or when <80% nail plate affected without lunula involvement 2

If Psoriasis-Related

Intralesional corticosteroids for nail matrix disease:

• Intralesional triamcinolone acetonide 5-10 mg/cc for <3 nails involved 2
• Topical high-potency corticosteroids ± vitamin D analogues for nail bed disease 2
• Calcipotriene combined with betamethasone dipropionate reduces nail thickness, hyperkeratosis, and onycholysis 2

Common Pitfalls to Avoid

• Don't use salicylic acid with calcipotriene if treating psoriatic nail disease—the acidic pH inactivates calcipotriene 2
• Don't expect rapid results—nail plate replacement takes 6-9 months for complete assessment of treatment efficacy 1
• Don't overlook fungal infection—splitting nails with discoloration or thickening require mycological evaluation before attributing to idiopathic causes 2
• Don't prescribe biotin or pyridoxine alone when combination therapy is available—monotherapy has significantly lower efficacy (10-11% vs 70% complete response) 1

Expected Outcomes

With appropriate treatment, expect partial response (>50% improvement) in an additional 30-39% of patients who don't achieve complete resolution with combination biotin/pyridoxine therapy 1. Total treatment duration typically requires 6-9 months to allow complete nail plate regeneration 1.