What are the causes and treatments for brittle nails?

Brittle Nails: Causes and Treatment

For idiopathic brittle nails, oral biotin supplementation at 2.5 mg daily is the most evidence-based treatment, showing improvement in 91% of patients after approximately 5.5 months of therapy. 1

Primary Causes

Brittle nails (characterized by splitting, flaking, crumbling, and loss of elasticity) affect up to 20% of the population, particularly women over 50 years of age. 2

Idiopathic Brittle Nail Syndrome

• Most cases are idiopathic, representing the primary form of nail fragility without identifiable underlying disease. 3, 2
• This is the most common presentation and should be the working diagnosis after excluding secondary causes. 4

Environmental and Occupational Factors

• Progressive dehydration of the nail plate is the most important environmental contributor to brittleness. 3
• Repeated water immersion and household chores are particularly damaging. 5
• Occupations requiring frequent hand washing or water exposure significantly contribute to nail changes. 6

Secondary Causes to Exclude

• Dermatological conditions: Lichen planus, psoriasis, Darier disease, and onychomycosis can all cause nail dystrophy with brittleness. 6, 7
• Systemic diseases: Hypochromic anemia, iron deficiency, peripheral vascular disease, endocrinopathies, and arthritic deformities of distal joints. 5
• Nutritional deficiencies: Biotin deficiency (rare), though supplementation benefits even those without documented deficiency. 7, 3
• Trauma: Repetitive trauma can result in abnormal nail appearance including ridging and brittleness. 6

Clinical Presentations

The main clinical patterns include: 2, 5

• Onychoschizia: Lamellar splitting (horizontal layering/peeling)
• Onychorrhexis: Longitudinal ridging and splitting
• Superficial granulation of keratin
• Worn-down nails

Treatment Approach

First-Line: Biotin Supplementation

Oral biotin 2.5 mg daily is the most effective systemic therapy, with 91% of patients showing definite improvement after an average of 5.5 months. 1 This represents the strongest evidence for any treatment modality in brittle nails. 7

• Biotin has been documented to successfully treat brittle nails (onychoschisis) in multiple studies. 7
• Treatment duration typically requires 5-6 months before significant improvement is observed. 1
• Even in the absence of documented biotin deficiency, supplementation remains beneficial. 3, 2

Preventive Measures (Essential Adjunct)

• Wear protective gloves (plastic over light cotton linings) during household chores and water exposure. 5, 8
• Avoid excessive moisture exposure and repeated friction/trauma. 6, 8
• Apply daily moisturizers/emollients to cuticles and periungual tissues. 7, 8
• Avoid cutting nails too short; trim straight across. 8

Additional Supportive Therapies

• Topical nail hardeners: Modified nail varnish base coats or dimethyl urea-based products (preferable to formaldehyde-containing products). 5
• Topical moisturizers and lacquers can restructure the nail plate and provide protection. 2
• Other oral supplements: Trace elements, amino acids (especially cysteine), and other vitamins may provide additional benefit, though evidence is weaker than for biotin. 3, 2

Common Pitfalls

• Failing to address environmental factors: Even with biotin supplementation, continued water exposure and trauma will undermine treatment success. 3, 5
• Expecting rapid results: Improvement requires months of consistent therapy since nails grow slowly. 1
• Missing secondary causes: Always evaluate for underlying dermatological or systemic diseases, particularly if brittleness is severe, rapidly progressive, or associated with other nail changes. 6, 2
• Inadequate treatment duration: Patients often discontinue therapy prematurely before the 5-6 month timeframe needed to see results. 1

When to Investigate Further

Obtain further evaluation if: 6

• Ridges or brittleness appear suddenly or change rapidly
• Associated with pain, inflammation, or nail separation
• Multiple nails affected with other dystrophic changes suggesting inflammatory disease
• Suspect fungal infection (obtain microscopy, culture, or PCR testing) 6