The darkening of the skin on both sides of the buttocks may be related to chronic eczema, ringworm and other diseases, but also can be seen in physiological factors.
1. chronic eczema is a kind of inflammatory skin disease, with a long time by the internal and external factors stimulation, local skin can be manifested as skin thickening, moss-like changes, skin pigmentation and itching.
2. ringworm is due to local skin infection ringworm bacteria and the formation of a skin disease, the local skin can appear clear boundary lesions, lesions can be brown, dark brown, due to prolonged scratching, the surrounding skin will appear black phenomenon.
3. Physiological factors. Repeated friction of the buttock skin due to prolonged sitting or walking can cause a large number of melanin particles to be deposited, and then some black pigmentation can be formed on the skin surface.
Due to the individual differences in clinical manifestations, please consult your doctor for details.