What causes the thumb nail to have vertical lines?

1. Trauma: 2. Lack of vitamin A: due to eating instant noodles and other fast food for a long time, do not often eat fruits and vegetables, resulting in a lack of vitamin A and other nutrients in the body, resulting in the thumb nail showing vertical striations. 3. Excessive fatigue: due to long hours of work, resulting in mental tension, resulting in serious lack of sleep, which will lead to the thumb nail showing vertical striations. 4. Disease: Such as iron deficiency anemia, renal dysfunction, pancreatitis, rheumatism and other diseases can lead to the phenomenon of vertical lines on the thumb nail.