What causes brittle nails with ridges?

Causes of Brittle Nails with Ridges

Brittle nails with ridges are most commonly caused by normal aging, but can also result from inflammatory conditions (lichen planus, psoriasis), chronic moisture exposure, fungal infections, nutritional deficiencies (particularly biotin), or repetitive trauma. 1, 2

Primary Etiologies

Age-Related Changes

• Vertical ridging is often a normal manifestation of aging as the nail matrix's ability to produce smooth nail plates diminishes over time, typically appearing as longitudinal striations running from cuticle to tip 1, 2
• This represents the most common cause in elderly patients and typically requires no treatment unless causing functional problems 1

Inflammatory Dermatologic Conditions

• Lichen planus causes nail thinning, longitudinal ridging, and other nail dystrophies through direct damage to the nail matrix 1, 2
• Psoriasis produces nail changes including ridging, though usually accompanied by other nail manifestations like pitting or onycholysis 1, 2
• These conditions require targeted treatment with intralesional triamcinolone acetonide 5-10 mg/cc for nail matrix involvement when affecting fewer than 3 nails 2

Infectious Causes

• Onychomycosis (fungal infection) accounts for 15-40% of all adult nail diseases and causes nail dystrophy with thickening, discoloration, and friable texture 2, 3
• Fungal infections more commonly affect toenails (80% of cases) than fingernails, which helps distinguish them from other causes 4
• Chronic paronychia from bacterial or fungal infection leads to proximal nail dystrophy with associated ridging, particularly in patients with occupational moisture exposure 2, 3

Environmental and Occupational Factors

• Chronic moisture exposure from occupations requiring frequent hand washing or water immersion contributes significantly to nail brittleness and ridging 1, 5
• Progressive dehydration of the nail plate from environmental factors plays an important role in nail brittleness 5
• Repetitive trauma results in abnormal nail appearance including ridging, with characteristic intact longitudinal epidermal ridges stretching to the lunula 1

Nutritional Deficiencies

• Biotin deficiency can cause brittle nails with ridging, though this is relatively rare in well-nourished individuals 4, 5
• Copper deficiency may contribute to nail changes, though this is uncommon except in specific populations (preterm infants, severe malnutrition, short gut syndrome) 4
• Evidence does not support routine supplementation of vitamin E, vitamin C, vitamin A, zinc, iron, copper, selenium, or vitamin B12 for improving nail health in well-nourished patients 6

Diagnostic Approach

Clinical Examination

• Examine all nails for pattern of involvement (number affected, distribution) and look for associated skin conditions that might explain nail changes 1
• Assess whether ridges are vertical (typically aging or inflammatory) versus horizontal (often medication-induced or systemic illness) 2
• Look for signs suggesting fungal infection: thickening, discoloration, friable texture, and predominant toenail involvement 3

Laboratory Testing When Indicated

• Direct microscopic examination with potassium hydroxide preparation and fungal culture on Sabouraud's glucose agar are essential if fungal infection is suspected 2, 3
• Calcofluor white staining significantly enhances visualization of fungal elements compared to standard KOH preparation 3
• Critical pitfall: Do not diagnose fungal infection based on appearance alone, as 50% of nail dystrophy cases are non-fungal despite similar clinical presentation 3

Management Principles

When to Seek Medical Evaluation

• Medical evaluation is recommended if ridges appear suddenly or change rapidly, are associated with pain, inflammation, or nail separation 1
• Sudden onset suggests inflammatory or infectious etiology rather than normal aging 1

Treatment Based on Etiology

• For idiopathic brittle nail syndrome: Oral biotin supplementation 2.5 mg daily has shown 91% improvement rates after average treatment of 5.5 months 6, 7, 8
• For inflammatory causes: Treat underlying condition with appropriate anti-inflammatory therapy (intralesional steroids for lichen planus/psoriasis, topical steroids for paronychia) 2
• For fungal infections: Antifungal therapy after confirmation by microscopy and culture 2, 3
• For moisture-related damage: Strict avoidance of excessive water exposure, wearing gloves during wet work 1, 5

Preventive and Supportive Measures

• Daily application of topical emollients to cuticles and periungual tissues helps prevent nail problems 2
• Protective nail lacquers can prevent brittle nails and provide structural support 2
• Gentle nail care, avoiding trauma-related factors, and wearing gloves while cleaning or working with chemicals 1

Common Pitfall

The most important clinical distinction is between normal age-related vertical ridging (which requires only reassurance and preventive care) versus pathologic causes (which require specific treatment). The key differentiating features are: sudden onset, rapid progression, associated pain or inflammation, predominant fingernail involvement with moisture exposure history (suggesting Candida), or predominant toenail involvement with thickening and discoloration (suggesting dermatophyte infection). 4, 1