Hi doctor i had black line at my fingers nails,,,maybe that is melanoma?

Monitor for change: A single dark brown or black vertical streak along your nail is how subungual melanomas show up. Look for a change over the next 2-3 months(take a photograph if possible) and then compare the change. Melanoma will grow and produce an area of elevation at the base of the nail(proximaly). Show it to a dermatologist if you think it has changed over a period of months.

ABCDEF: A modification of the cutaneous melanoma ABCDE applied to nails: A: Age (5th-7th decade), African Americans, Asian, native Americans. B: Brown to Black. Breadth greater than 3 mm. C: Color change. D: Digit most commonly involved. E: Extension of black color onto skin. F: Family history.