There is a red spot on the glans then the possible causes: first, glansitis, when the occurrence of bacteria, fungi, trichomonas and other pathogenic bacteria infection after the local red spot may appear, accompanied by local redness, swelling, pain, etc.. The first one is the presence of the pathogenic bacteria, such as bacteria, trichomonas and other pathogens, which can cause local red spots, accompanied by redness, swelling and pain. It is necessary to wash regularly to maintain local cleanliness, or circumcision can disappear on its own; third, sexually transmitted diseases, such as syphilis spiral infection, may appear local red dots, followed by the formation of mucosal ulceration or the formation of hard chancre. The diagnosis of syphilis needs to be further confirmed by a syphilis etiology test. The disease is usually associated with unclean sexual contact, but if there is no unclean sexual contact, syphilis is not considered.