Ulcers on the inner side of the foreskin without nodules may be caused by factors such as glans inflammation, prepuce inflammation, syphilis infection and so on. 1. glansitis: usually do not pay attention to glans hygiene, infection with bacteria or other microorganisms, may cause glansitis, which leads to glans redness, red rash, not timely treatment, the symptoms may involve the inner foreskin, resulting in the epidermis with ulcers formed. 2. Foreskin infection: related to infection, trauma and other irritating factors, the patient will have redness and swelling of the foreskin, glans, erosion, ulcers, etc. Symptoms may occur on the surface of the foreskin, or on the inner side of the foreskin. 3. Syphilis infection: mainly due to the infection of syphilis spirochetes caused by sexually transmitted diseases, the disease will also be transmitted through mother-to-child transmission, blood transmission, the main manifestations of the skin rash, pimples or blisters, vesicles. Ulcers on the inner side of the foreskin without nodules, in addition to the above factors, may also be related to circumcision, penile cancer and other diseases, it is recommended to consult a doctor as soon as possible, and diagnosis and analysis through syphilis serology, pathology biopsy, and then according to the results of targeted treatment.