What causes ridges in the nails?

Causes of Nail Ridges

Nail ridges are primarily caused by aging, trauma, nutritional deficiencies, systemic diseases, and dermatological conditions, with the specific pattern and appearance of ridges helping to determine the underlying cause. 1

Types of Nail Ridges

Longitudinal Ridges (Running from Cuticle to Tip)

• Age-related changes: Most common cause in older adults due to slowed nail growth and altered nail matrix function 2
• Nutritional deficiencies: Particularly iron deficiency anemia (may present with koilonychia or "spoon-shaped" nails) 1, 3
• Systemic conditions:
  • Connective tissue disorders (may present with telangiectasia and ridging) 3
  • Endocrine disorders (including thyroid dysfunction) 4
  • Inflammatory bowel disease 3

Horizontal Ridges (Running Side to Side)

• Beau's lines: Horizontal depressions indicating temporary disruption of nail growth due to:
  • Severe illness or systemic disease 3
  • Physical trauma to the nail matrix 1
  • Exposure to cold temperatures in patients with Raynaud's disease 3
• Muehrcke's lines: Paired white bands that indicate hypoalbuminemia 3
• Mees' lines: White transverse lines that may indicate arsenic poisoning or other systemic illnesses 1

Common Causes by Prevalence

1. Age-related changes: Longitudinal ridging increases with age due to:

   • Reduced peripheral circulation 5
   • Slower nail growth 5
   • Changes in nail matrix function 2

2. Trauma and environmental factors:

   • Repeated nail trauma 1
   • Excessive exposure to water or chemicals 6
   • Occupational factors causing nail dehydration 6

3. Dermatological conditions:

   • Psoriasis (may cause pitting and ridging) 1
   • Lichen planus (can cause thinning and ridging) 1
   • Onychomycosis (fungal infection affecting nail appearance) 5, 1

4. Nutritional deficiencies:

   • Iron deficiency 1, 3
   • Protein deficiency 7
   • Deficiencies in vitamins (particularly biotin) and minerals 6, 7

5. Systemic diseases:

   • Endocrine disorders (thyroid dysfunction) 4
   • Connective tissue disorders 3
   • Vascular diseases 4
   • Pulmonary diseases (may present with clubbing) 3

Diagnostic Approach

When evaluating nail ridges, consider:

• Pattern of ridging: Longitudinal vs. horizontal
• Associated nail changes: Discoloration, thickening, brittleness, or separation
• Systemic symptoms: Presence of other health concerns
• Age of patient: Longitudinal ridges are more common and often benign in older adults 2

Clinical Pearls and Pitfalls

• Important caveat: Approximately 50% of nail dystrophies are non-fungal in origin, highlighting the importance of considering multiple causes 1
• Diagnostic error risk: Assuming all brittle or ridged nails are due to iron deficiency can lead to misdiagnosis, as approximately 20% of the population has brittle nails with multiple potential causes 1
• Serious conditions to consider: Persistent single nail dystrophy may require biopsy to rule out malignancy 1
• Treatment approach: Address the underlying cause rather than just the nail appearance 1

Prevention and Management

• Remove predisposing factors (excessive water exposure, harsh chemicals) 1
• Consider nutritional supplementation with biotin, amino acids, and minerals for brittle nails with ridging 6, 7
• Maintain proper nail hygiene and avoid trauma 1
• Treat underlying conditions (dermatological disorders, systemic diseases) 1