The swelling of the circle behind the glans may be caused by acute injury, prepuce glansitis, allergic factors. 1. Acute injury: for example, too much force or excessive pressure during sex may lead to local damage, which can cause a circle behind the glans to swell, which may be accompanied by pain and subcutaneous bruising and other clinical symptoms, can be improved by oral anti-inflammatory and analgesic drugs, such as ibuprofen, diclofenac sodium and so on. 2. Foreskin glansitis: men have a long foreskin, such as daily not pay attention to hygiene, may be induced by the foreskin glansitis. After the infection is aggravated, it will lead to a circle of swelling behind the glans, accompanied by itching, pain, redness and other symptoms, can be treated with topical erythromycin ointment, clotrimazole ointment and other drugs. 3. Allergic factors: such as contact with some stimulating toiletries, resulting in localized allergic reaction of the penis, will make the local swelling, may also be accompanied by intense itching and tingling and other symptoms. You can use topical glycerine lotion, tacrolimus ointment and other medications, and in severe cases, you need to take oral medications, such as cetirizine and loratadine. The ring behind the glans is swollen, it is recommended to consult a doctor for examination, clear causative factors, timely treatment, in the treatment period, to follow the doctor’s instructions, safe and reasonable use of drugs, do not indiscriminate use of drugs.