13. Red Streaks
Red streaks are huge indications that you just can’t ignore. If you notice a red streak occasionally on one nail, it is probably a broken blood vessel and you can put your mind at ease. But if this becomes a constant occurrence present across three or four fingers, then you might want to inspect this a little bit more. If the redness reaches out to the sides of the nail it is considered as a sign of Lupus, but if the red streaks get a darker color it is an indication of a heart disease. Consult a physician and run the required tests.