Swelling in the male coronal area may be caused by acute injury, infectious factors, allergic factors. 1. Acute injury: for example, the coronal region of the penis has been over-squeezed, resulting in localized damage, which will make the coronal region of the symptoms of swelling, may also be accompanied by pain and subcutaneous bruising. 2. Infection: men do not pay attention to the lower body care, do not often wash the lower body, and do not often change the underwear, may lead to bacterial infection of the penile area, the infection aggravated will lead to the coronary groove area of a circle of swelling, may be accompanied by itching, pain and other symptoms. 3. Allergic factors: such as condom allergy or toiletries allergy, resulting in allergic reactions in the penile coronal region, can make the coronal region swollen, may also be accompanied by intense itching, the local can appear red pimples. Men with a swollen coronal area, indicating the existence of abnormal conditions, it is recommended to seek medical attention for detailed examination and treatment.