A red blood clot at the foreskin may be caused by factors such as acute injuries, torticollis, warts and so on. 1. Acute injury: for example, excessive stimulation or external blows, resulting in localized damage to the foreskin, may make the local appearance of red blood clots, may also be accompanied by obvious pain and subcutaneous bruising. 2.glans phimosis: the presence of glans phimosis, due to the presence of infection, can make the localized swelling, similar to the red blood clots, accompanied by pain, itching and other symptoms, in severe cases, can be broken and pus. 3. warts: belong to a sexually transmitted diseases, mostly related to unclean sex, can make the foreskin localized cauliflower pattern swelling, similar to red blood clots, may also be accompanied by mild itching and tingling, and has a certain degree of contagious. A red blood clot at the foreskin, it is recommended to go to the urology department of the hospital for appropriate examination and treatment, to avoid delaying the condition.