Men with blisters on the penis are mainly considered to be related to glansitis, eczema, allergies, genital herpes and sexually transmitted diseases. 1. glansitis: mainly caused by bacterial infection, its clinical manifestations are varied, some patients may appear blisters, itching, redness and swelling and other symptoms. 2. Eczema: it can lead to pimples, blisters and other symptoms in the affected area, accompanied by itching, tingling and other uncomfortable symptoms. 3. Allergy: pimples, blisters, itching and other symptoms may also occur after penile allergy. 4. Genital herpes: mainly caused by infection with the genital herpes virus, which can lead to a red rash on the affected area and develop into blisters. 5. Sexually transmitted diseases (STDs): such as syphilis and condyloma acuminatum, which can also lead to blisters on the affected area, accompanied by itching and other uncomfortable symptoms. The causes of such symptoms are complex, and it is recommended to seek medical examination as soon as possible to confirm the diagnosis of the condition, and treatment under the guidance of the doctor.