Excluding the redness and swelling caused by pubic trauma, the causes of redness and swelling in the pubic area of young boys mainly include circumcision and glans, urinary tract infections, and pubic skin factors. 1. circumcision: mainly due to foreskin scale or bacterial infection, mainly will show the symptoms of redness, swelling, erythema and other symptoms at the mucous membrane of the glans skin. 2. urinary tract infection: when urinary tract infection, bacteria may enter into the urethra, which may lead to the redness and swelling of the foreskin and urethral opening, and if the symptoms are more serious, it may also produce purulent secretion. 3. pubic skin factors: if the pubic skin of the boy appeared to be allergic, it may be caused by contact with their own allergies to clothing, detergents and other substances, local redness and swelling. Parents are advised to take the boy to the doctor to identify the exact location of the redness and swelling in the pubic area, and find out the cause of the redness and swelling, so as to take corresponding treatment measures.