Skin with one white and one black may be caused by simple furuncle, polymorphic solar rash, vitiligo, sweat patches and other reasons. 1. Simple furuncle: autoimmune deficiency, trauma, overwork and other reasons can lead to the formation of simple furuncle. Initially, fever, lymph node swelling and pain, loss of appetite and other symptoms, with the development of the disease, can lead to facial lesions, manifested in the local skin of a white and a black situation. 2. Polymorphic sun rash: the disease is usually associated with a variety of photosensitizers, belonging to the delayed-photo-allergic reaction. When allergies come into contact with photosensitizers, it can lead to the appearance of eczema-type herpes. When the herpes ulcers and scabs, there will be hyperpigmentation, which will lead to a piece of white and a piece of black skin phenomenon. 3. Vitiligo: When melanocytes are destroyed, all parts of the human skin may lead to white spots, resulting in the skin appearing white and black. 4. Sweat patches: When Malassezia violates the cuticle of the skin, it leads to fungal infection of the skin. As the disease develops, it may lead to skin damage, resulting in localized hyperpigmentation, leading to the appearance of white and black skin. When the skin is white and black, it is recommended to go to the hospital skin as soon as possible, to clarify the cause of the disease, and actively carry out targeted treatment.