What causes dry splitting nails, also known as onychoschizia, in older adults?

What Causes Dry Splitting Nails (Onychoschizia)

The primary cause of dry splitting nails is repeated exposure to water followed by dehydration, which progressively damages the nail plate structure through cycles of hydration and dehydration. 1

Primary Mechanism: Environmental Water Exposure

The most well-established cause of onychoschizia is repeated wetting and drying cycles that mechanically disrupt the nail plate structure 1:

• Experimental studies demonstrate that normal nails develop typical splitting changes after 21 days of repeated water exposure followed by dehydration 1
• Progressive severity increases with prolonged wetting-drying cycles, with scanning electron microscopy showing unattached individual cells and prominent separation by 3 weeks 1
• This mechanism explains why onychoschizia affects up to 20% of the population, particularly women over 50 years of age, and why fingernails are more commonly affected than toenails 2

Age-Related Factors in Older Adults

In elderly patients, the nail matrix's diminished ability to produce smooth nails contributes significantly to brittle, splitting nails 3:

• Vertical ridging with splitting or brittleness characterizes age-related nail changes 3
• Reduced peripheral circulation, slower-growing nails, and difficulty maintaining nail hygiene compound the problem in those over 60 years 4
• The correlation between increasing age and nail problems is attributed to suboptimal immune status, larger and distorted nail surfaces, and increased nail injury 4

Secondary Causes to Rule Out

Before attributing splitting nails to idiopathic causes, exclude these important secondary etiologies:

Fungal Infection

• Fungal infections present with thickening, discoloration, and friable texture—not just splitting 3
• Critical pitfall: Do not assume fungal infection without laboratory confirmation via KOH preparation and fungal culture, as 50% of dystrophic nails are non-fungal despite similar appearance 5
• Examine for soft, friable texture (suggesting fungal) versus hard, brittle texture (non-infectious causes) 3

Inflammatory Dermatologic Conditions

• Lichen planus produces nail thinning with longitudinal ridging and splitting 3
• Psoriasis causes nail thinning and longitudinal ridging with associated pitting or onycholysis 3
• Look for associated nail changes like subungual hyperkeratosis or discoloration that suggest inflammatory disease rather than simple aging 3

Occupational and Chemical Exposure

• Chronic moisture exposure from wet occupations leads to chronic paronychia with proximal nail dystrophy and ridging 3
• Organic solvents, detergents, and harsh chemicals contribute to nail plate damage 1
• Assess for paronychia (nail fold swelling/erythema) suggesting Candida infection with occupational moisture exposure 3

Medication-Induced Changes

• Cytotoxic drugs (taxanes, anthracyclines, fluorouracil, EGFR inhibitors) commonly cause nail abnormalities 6
• Tetracyclines, quinolones, retinoids, and psoralens can cause nail plate detachment and discoloration 6
• Most drug-induced nail disorders resolve after discontinuation, though complete resolution may take several years 6

Systemic Conditions

• Diabetes increases risk of nail problems through poor circulation, neuropathy, and impaired wound healing 4
• Immunodeficiency states (HIV, transplant recipients, immunosuppressive treatments) increase susceptibility to nail infections and dystrophy 4
• Nutritional deficiencies may contribute to brittle nail syndrome 2

Diagnostic Approach Algorithm

Follow this systematic evaluation:

1. Examine nail texture and appearance 3:

   • Hard, brittle texture with splitting = likely environmental/idiopathic
   • Soft, friable texture with discoloration = suspect fungal infection
   • Nail fold swelling/erythema = consider Candida with moisture exposure

2. Look for inflammatory features 3:

   • Pitting, onycholysis, subungual hyperkeratosis = inflammatory disease
   • Isolated vertical ridging with splitting = likely aging or environmental

3. Obtain laboratory confirmation when indicated 5:

   • KOH preparation and fungal culture if fungal infection suspected
   • Remember: 50% of dystrophic nails are non-fungal despite appearance

4. Assess occupational and environmental exposures 3:

   • Wet occupations requiring protective counseling
   • Chemical exposure history
   • Frequency of water contact

5. Review medications and systemic conditions 6, 4:

   • Current medications that may affect nails
   • Diabetes, immunodeficiency, or other systemic diseases

Management Implications

Understanding the cause guides treatment:

• For environmental/idiopathic onychoschizia: Apply daily topical emollients to periungual folds and nail plate, use protective nail lacquers to limit water loss, and avoid prolonged water soaking and harsh chemicals 3
• For confirmed fungal infection: Treat with systemic antifungal agents (terbinafine or itraconazole) only after mycological confirmation 3
• For inflammatory causes: Consider intralesional triamcinolone or topical steroids with vitamin D analogs depending on extent of involvement 3
• For occupational exposure: Provide guidance on protective measures like wearing gloves while cleaning 3

Common pitfall: Neglecting to counsel patients with chronic moisture exposure about protective measures leads to treatment failure regardless of other interventions 3