If the curved white line above the nail is about 0.2 centimeters away from the end of the nail, this is a normal crescent line, which every healthy person will have, and is a manifestation of the production of the nail bed gradually replacing the new nail. If irregular white lines suddenly appear on the nail, consider that it is caused by a sharp instrument scratch, if there is no pain and discomfort it is recommended that observation is the main focus, no need for special treatment. Patients with fungal infections may also have white lines on the nails, accompanied by symptoms such as thickening and yellowing of the nails, which is considered to be gray nails, and it is recommended to take oral terbinafine tablets for treatment, which needs to be taken continuously for 6-12 weeks. In children, due to the lack of vitamins or trace elements in the body, there will also be curved white lines on the nails, and it is recommended to supplement vitamins and trace elements in a timely manner. It is recommended to have a balanced diet and avoid picky eating or partiality, so as to avoid the lack of vitamins and trace elements in the body due to insufficient intake.