Depends on the color: And direction. Transverse white lines can be fungal or a minor injury; longitudinal white lines may be damage to the nail plate; a dark line can be normal, especially in dark-skinned people, or it could be a melanoma. There needs to be more information and examination to answer more accurately.
Answered 3/20/2014
4.9k views
Anything: From melanoma to fungal infection. See either podiatrist or dermatologist. Don't mean to scare you about melanoma but it is possible, happened to bob marley.
Answered 9/21/2013
4.9k views
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