Erythema of glans may be capillary expansion, or other male diseases, such as glansitis, phimosis, etc. need to be judged according to the symptoms. 1. capillary dilatation: due to incorrect sleeping position, the genital organs under pressure is easy to appear glans erythema, which is caused by capillary dilatation, the need to adjust the sleeping position, and standing for a period of time can be subsided on their own. 2. Glans inflammation: not paying attention to personal hygiene, unclean life, etc., may cause glans inflammation, the glans area will appear erythema, and there will be swelling and pain. 3. Circumcision: Men with long foreskin can’t turn out the foreskin, which is easy to harbor bacteria and cause circumcision, and there will be erythema on the top of the glans, as well as itchiness and tingling sensation. The causes of erythema of the glans are many, not necessarily caused by capillary expansion, if accompanied by other symptoms, it is recommended to go to a professional men’s hospital.