Swelling of the foreskin in children may be caused by acute injury, circumcision, skin allergy and other factors. 1. Acute injury: for example, foreign body stimulation or excessive pressure, resulting in penile epidermis damaged and congested, it will cause symptoms of swelling, may also be accompanied by pain. 2. Circumcision: children do not pay attention to the care of the foreskin area, a long time without cleaning, may breed bacteria and fungi, producing inflammatory substances, stimulated by inflammatory substances, will make the foreskin swelling, accompanied by redness, itching and other symptoms. It is common in children who are circumcised and circumcised. 3. Skin allergy: Parents buy poor quality underwear for children, after wearing, may make the foreskin localized allergic reaction, it will cause swelling, and accompanied by intense itching. Swelling of the foreskin in children indicates the presence of abnormalities, and parents are advised to take their children to the urology department of the hospital for examination and treatment.