Transverse linear depressions grooves in the fingernail are referred to as Beau's lines. They develop when a patient experiences an event that disrupts normal nail growth.


Causes of Beau's lines:

(1) trauma

(2) high altitude

(3) chemotherapy or bone marrow transplantation

(4) other medications or toxin exposures

(5) malnutrition

(6) exposure to cold temperatures with Raynaud's disease

(7) severe febrile illness


Usually Beau's lines affects all or most of the nails on the hands and feet and is bilateral. A single nail may be affected if the nailbed is crushed. Trauma to a wrist or hand may cause the lines to appear in several nails of one hand.


Multiple lines may occur in the same nail if the patient had recurring insults, such as several rounds of chemotherapy or a serious illness with relapse.


Rate of progression:

(1) appear about 6-8 weeks after the insult

(2) move at about 1 mm every 6 to 10 days

(3) shed at 5-6 months


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