There is a little red pimple on the glans penis, which is considered to be caused by the following reasons: First, balanitis is a common disease. Generally, the foreskin is too long and scales are produced, which is not cleaned up in time. It is also possible that sexual partners suffer from certain gynecological diseases and fail to take safety measures during sexual life, leading to male balanitis caused by cross-infection. Secondly, pearl rash is a normal physiological phenomenon, which occurs in about 24% of adults. It doesn't hurt, it doesn't itch, it's not contagious and it doesn't need treatment. Pearl rash may exist for a long time or disappear. Third, genital herpes, caused by herpes virus infection, starts with red papules, then develops into blisters, and finally may appear ulceration and erosion. Fourth, condyloma acuminatum, condyloma acuminatum is a sexually transmitted disease, starting with tiny red papules, so we must pay attention to condyloma acuminatum.