What are Beau's lines (transverse leukonychia)?

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Last updated: March 7, 2025View editorial policy

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From the Guidelines

Beau's lines are horizontal depressions or grooves that run across the fingernails or toenails, indicating a temporary disruption in nail growth, and are typically associated with systemic stressors such as severe infections, malnutrition, or exposure to certain medications, as noted in a recent study 1. These lines typically appear when an illness, injury, or other stressor affects the body, causing the nail matrix to temporarily slow or stop producing nail cells.

Common Causes of Beau's Lines

  • Severe infections
  • Malnutrition
  • Uncontrolled diabetes
  • Zinc deficiency
  • Major surgery
  • Exposure to extreme cold
  • Certain medications, such as taxanes, which can cause nail changes, including onycholysis and Beau's lines, as reported in a study published in the Annals of Oncology 1 No specific medication is needed to treat Beau's lines, as they will naturally grow out with the nail over time (typically 3-6 months for fingernails and 6-12 months for toenails).

Management of Beau's Lines

  • Address the underlying cause of the disruption
  • Protecting your nails from trauma
  • Maintaining good nutrition to help prevent future nail disruptions If Beau's lines appear without an obvious trigger, or if they occur repeatedly, medical evaluation is recommended to identify potential underlying health issues, as suggested by a study on dermatological toxicities related to anticancer agents 1. The appearance of these lines serves as a visible timeline of past physiological stress, with the distance from the cuticle indicating approximately when the disruption occurred.

From the Research

Definition and Characteristics of Beau's Lines

  • Beau's lines are transverse grooves or depressions in the nail plate that result from a temporary interruption of the growth of the proximal nail matrix 2, 3, 4, 5, 6
  • They can be triggered by infections, systemic diseases, local trauma, drugs, and other factors 2, 3, 4, 5, 6
  • Beau's lines appear as horizontal grooves that traverse the nail plate and can be bilateral or unilateral 2, 3, 4, 5, 6

Causes and Associations of Beau's Lines

  • Beau's lines can be associated with severe systemic illnesses, such as COVID-19 2, and may indicate a higher probability of reinfection and rehospitalisation
  • They can also be caused by local trauma, such as a fractured and immobilized wrist 3 or a fingertip crushing injury 4
  • In some cases, Beau's lines may be associated with underlying conditions, such as lymphoma 6
  • Beau's lines can appear in individuals of all ages, including infants, and may be related to intrauterine distress or other perinatal factors 5

Clinical Significance of Beau's Lines

  • The appearance of Beau's lines may indicate past severe illness or infection, and can provide an important diagnostic clue 2, 6
  • Beau's lines can be a useful indicator of the severity of a patient's condition and may be associated with a higher risk of complications or recurrence 2
  • The presence of Beau's lines should be carefully evaluated during physical examination, as they may provide valuable information about a patient's medical history and underlying conditions 2, 6

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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