Beau's Lines:
Information for adults

Beau's lines are horizontal (transverse) depressions in the nail plate that run parallel to the shape of the white, moon-shaped portion of the nail bed (lunula) seen at the nail's origin. They result from a sudden interruption of nail keratin synthesis and grow distally with the nail plate. As the nail grows, the Beau's lines can disappear.

Beau's lines can be caused by trauma or local disease involving the nail fold. They can vary based upon the width or depth of the depression, reflecting the duration or extent of the damage. When Beau's lines are present in all nails at a similar location on the nail plate, they are likely to have a systemic cause. They may also result from metabolic, inflammatory, or traumatic influences.