Round white patches on the back of the buttocks may be due to birthmarks, vitiligo, florid chaff rash and other causes. 1. birthmark: it is due to abnormal proliferation of skin tissues during development, which makes the skin surface appear abnormal in shape and color, and plaques appear on the skin at birth or after birth. if there is a birthmark on the back of the buttocks, it can be manifested as the symptom of round white spots on the back of the buttocks, such as apheresis, anaemia nevus, and so on. 2. Vitiligo: is due to the destruction of skin melanocytes, so that the lack of melanin in the skin caused by the phenomenon of white patches, can occur in all parts of the human body, if the body suffers from vitiligo disease, will lead to the buttocks behind the symptoms of round white patches. 3. florid chaff rash: the skin behind the buttocks of the skin tissue is Malassezia involved in the skin stratum corneum caused by the skin white, yellowish or brown dotted rash, and gradually developed into a flaky phenomenon, which can be manifested as a buttocks behind the round white spots of symptoms, the skin of the skin, the skin of the skin, the skin of the skin, the skin of the skin, the skin of the skin, the skin of the skin. The causes of round white spots behind the buttocks are many, it is recommended to go to the hospital for examination and diagnosis in a timely manner, clear the cause of the disease to give targeted treatment, in order to avoid the impact on the health of the body.