Are dark lines in finger and toenails for a long period a concerning issue?

Q. I have dark lines in finger and toenails since childhood. Is this a serious condition?

Answered by
Dr. Suvash Sahu
and medically reviewed by Dr. Vinodhini. J
This is a premium question & answer published on Mar 24, 2020 and last reviewed on: Aug 10, 2023

Hello doctor,

I have a dark line in my toenail for a long time, since I was a kid I realize that, but never came into my mind that could be dangerous. The same happened to my fingernail many years after I became an adult. I would like to know if it is something serious and should I care about it?



Welcome you to

I have seen your query and examined your given picture. (attachment removed to protect patient identity). It seems you have developed melanonychia. The cause of this are many such as inflammatory nail diseases like lichen planus, racial, nevus in nailbed and rarely melanoma. You need to go for nail biopsy for confirmation.

Thank you doctor,

Does this condition refers to both toenail and the fingernail? I kindly would like to know more about the possibility of this toenail be an inflammatory disease for so long time. I remember this line since I was a kid at least. I probably have progressive macular hypomelanosis (I never go for biopsy) there is any possibility for this be linked? I have tested for fungal and the test result was negative.



Welcome back to

I have seen your query. You can take tablet Biotin 10 mg once daily for three months. It can treat the nutrients aspects too. Biopsy will rule out other possible causes. And accordingly, treatment can be advised.

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