The white streaks on the arms may be the appearance of swelling lines that are old. As the swelling lines grow in the early stage, it may be due to sudden thickening of the arm or prolonged localized exercise, forming a break in the elastic and collagen fibers below the local skin tissue, forming a red streak-like appearance in the early stage, but as time migrates, the red appearance may gradually fade and be replaced by a white streak-like appearance. In addition to swelling lines, white streaks may also be formed by anaplastic nevi, especially linear anaplastic nevi, which exhibit a white streak-like appearance.