Bleeding from sebaceous cysts can be caused by broken capillaries and bacterial infections. 1. broken capillaries: sebaceous cysts are benign hyperplasia, may be covered with capillaries, if the cysts to extrusion, may be the cysts around the blood vessels will be squeezed, resulting in blood from the skin surface of the openings out, so that the subcutaneous cysts extrusion of the symptoms of blood. 2. Combined bacterial infection: If improper care is not taken, it will lead to the growth of bacteria in the local openings, causing local combined bacterial infection, which will lead to symptoms such as congestion, redness, swelling and pain on the surface of the skin, and when squeezed by hand, it will expand the inflammatory invasion to the surrounding area, destroying the normal tissues around it, and when the inflammation invades the local capillaries and causes damage to them, it will also lead to the outflow of blood. Therefore, sebaceous cysts can not be squeezed at will, and need to be surgically removed to be able to heal themselves. It is recommended that patients go to the hospital in time, under the diagnosis of the doctor, according to the patient’s specific condition, targeted treatment.