Erythema of the glans is painless and itchy, which may be caused by glansitis, prolonged foreskin, bacterial infection and other factors. 1. Glans inflammation: glans inflammation leads to erythema of the glans without pain and itchiness, mainly caused by bacterial infection, after the emergence of glans inflammation at the beginning of the patient will not have any symptoms, but after a period of time stimulation will appear erythema of red spots itching and pain symptoms. 2. Hyperemesis gravidarum: hyperemesis gravidarum leads to erythema of the glans without pain and itching, most of them are also caused by bacterial infection, mainly because the patient’s foreskin is not cleaned in place, which leads to dirt stimulation of the glans causing symptoms. 3. Bacterial infection: erythema on the glans, painless and itchy, may also be caused by bacterial infection, due to the patient does not pay attention to their own private hygiene, resulting in bacterial viruses breeding caused by infection symptoms. After the appearance of the above symptoms, patients had better go to the hospital in time for examination, and then according to the doctor’s advice for treatment.