Red spots on the penis may be caused by glansitis, eczema, syphilis and other diseases. 1.glans:glans is related to many factors, considering bacterial infection and other factors. The main symptoms of patients are glans mucosal edema, erythema, erosion, local itching and other symptoms, some patients will also be accompanied by pain, urinary irritation, itching, pain and other symptoms. 2. Eczema:The etiology of eczema is still unclear, considering that it is due to the body’s internal, external, psychosocial and other factors. Patients will appear erythema, edema, corn-sized papules and other symptoms, eczema patients also have itching, flaking and other manifestations. 3. Syphilis: Syphilis is mainly caused by syphilis spirochete infection, patients can appear in the penis small erythema, inguinal or lymph node swelling and other symptoms. Patients with syphilis also experience mild itching, fever, vomiting and other symptoms. Patients with red spots on the penis should go to the hospital in time to find out the cause of the disease and take treatment measures under the guidance of the doctor to avoid aggravating the condition.