There are red dots under the glans then possible causes: first, the occurrence of glansitis, can appear local red dots, accompanied by pain, accompanied by itching and other symptoms, mostly seen in patients with long foreskin or prepuce or poor local hygiene exists, there is a foreskin scale chronic stimulation or have unclean sexual contact, infected with relevant pathogens, can appear local appear small red dots. It is necessary to conduct relevant pathogenic laboratory tests, such as bacterial smear tests or mycoplasma, chlamydia and other related tests, to confirm the diagnosis and give symptomatic drug treatment. Secondly, if there is an allergic reaction, there can be local red dots with local itching, there can be other parts of the body with the same similar red dots, need to clarify whether there is allergic contact or take allergy drugs, if necessary, need to give anti-allergy treatment. Third, if suffering from sexually transmitted diseases, such as herpes virus infection or syphilis, gonorrhea, etc., may lead to the local appearance of small red dots, with the progress of the disease can subsequently form herpes, vesicles or the formation of other corresponding lesions. If a patient has a history of unclean sexual contact, it is recommended to undergo sex-related pathogenic testing, such as syphilis testing, gonococcal mycoplasma, chlamydia testing or herpes virus testing.