7 doctors weighed in:
Why do my fingernail have lines?
7 doctors weighed in

David Miller
Family Medicine
6 doctors agree
In brief: Lots of reasons
When you say "lines" it is difficult to say as there are many types of lines.
The most common lines seen are longitudinal (running along the length of the nail). More specifically, longitudinal melanonychia means dark lines along the nails. This can be variant of normal, particularly in persons with dark skin. However, any new line of pigmentation should be evaluated by a dermatologist.

In brief: Lots of reasons
When you say "lines" it is difficult to say as there are many types of lines.
The most common lines seen are longitudinal (running along the length of the nail). More specifically, longitudinal melanonychia means dark lines along the nails. This can be variant of normal, particularly in persons with dark skin. However, any new line of pigmentation should be evaluated by a dermatologist.
David Miller
David Miller
Answer assisted by David Miller, Medical Student
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