Red blisters on the genitals may be related to eczema, genital herpes, and glans phimosis, among other causes. 1. Eczema: genitals in a humid environment for a long time may lead to localized eczema, which can be manifested as red blisters. 2. Genital herpes: due to long-term inattention to personal hygiene or unclean sexual intercourse and other reasons, may lead to viral infection, induced genital herpes, the appearance of the genitals with red blisters. 3. Puniculitis: when bacteria and other pathogens infect the penis, it can cause puniculitis, resulting in red blisters on the genitals. Red blisters on the genitals may also be caused by other factors, it is recommended that the patient go to the regular hospital in time to clarify the cause of the disease, under the guidance of the doctor for standardized treatment, and strive for early recovery.