A small white spot on the leg can be seen as a birthmark, or it may be a sign of hypopigmentation. The actual fact is that you can find a number of reasons for skin hypopigmentation, such as vitiligo, halo nevus, white furfurace, idiopathic punctiform pigmentation reduction, age-related white spots, etc. 1, vitiligo: individuals with genetic traits under the stimulation of a variety of internal and external factors, resulting in impaired melanogenesis, epidermis, mucous membrane melanin particles reduced or disappeared, showing a variety of sizes and shapes of depigmented white spots, the skin of the head, face, neck and trunk The skin of the head, face, neck and trunk may be involved; 2. Dry scaly white spots with unclear edges; 4, idiopathic punctiform hypopigmentation: a degenerative skin lesion, clinically visible irregularly shaped milky white spots, mostly found on the extremities, face and trunk. This disease is mostly caused by genetic, photodamage and aging resulting in skin melanocyte loss, it is recommended to seek medical treatment as early as possible; 5. may lead to white spots on legs. However, there are other symptoms, such as scaling or itching on the skin surface at the onset of lichen planus. Some of the symptoms can recover on their own after the primary disease is cured.