Black and red color on the scrotum may be caused by acute injury, scrotal eczema, infection factors. 1. Acute injury: such as excessive pressure or external blows, resulting in localized skin damage to the scrotum, can cause subcutaneous bruising, will make the local presence of black and red, accompanied by pain, swelling and other symptoms. 2. Scrotal eczema: may be related to dietary factors, environmental factors, can make the scrotum area appear red pimples, accompanied by itching and tingling, a long time without treatment, may deepen the pigmentation, there will be black red. 3. Infection factors: the scrotum area folds as well as more pores, do not pay attention to daily care, may induce infections, such as fungal infections, lasting for a long time, will lead to the scrotum localized black-red, accompanied by itching, peeling and other symptoms. If there is a dark red color on the scrotum with obvious abnormal symptoms, it is recommended to consult a doctor for appropriate examination and treatment to avoid adverse effects.