What can lead to the appearance of Beau's lines in nails?

Beau's lines are transverse grooves or indentations that appear on the surface of the nails, and their formation is commonly associated with systemic illness or trauma. This is because Beau's lines occur when there is a temporary interruption in the growth of the nail matrix, which can be caused by various factors affecting overall health or physical stressors, such as severe illness, infections, or significant physical trauma.

The condition reflects a moment where nail growth is hindered, and once the body recovers, the growth resumes, leading to distinctive grooves that can be seen in the nail's surface as it continues to grow out. Therefore, understanding that Beau's lines result from systemic health issues or trauma helps to recognize their significance in indicating other underlying health concerns.