The patient’s redness and swelling of the coronal sulcus may be caused by excessive friction, circumcision, warts and so on. 1. Excessive friction: when the patient wears ill-fitting pants or participates in strenuous exercise, it may lead to excessive friction in the glans area, thus causing symptoms such as redness and swelling of the coronal sulcus. 2. circumcision: circumcision is an inflammatory lesion that occurs in the head of the penis, foreskin and coronal groove, mainly manifested as redness, swelling, burning pain and other symptoms of the circumcision glans, coronal groove redness and swelling may be caused by circumcision glans. 3. Acute warts: Acute warts, also known as genital warts, is a common sexually transmitted disease caused by human papilloma virus infection, men appearing coronary urethra red swelling may be caused by the Acute warts. It is recommended that the patient timely medical examination, clear cause of the targeted treatment, in the life of a good habit, pay attention to personal hygiene, to avoid unclean sex.