Male genital blood blisters may be related to glans, trauma, allergic skin vasculitis and other diseases. It is recommended that the patient go to the hospital in time to clarify the cause of the disease. 1. Glans inflammation: male foreskin is too long, do not pay attention to hygiene, etc. may cause glans inflammation. The main manifestation is that the glans is red, swollen, painful, itchy and uncomfortable. In severe cases, blisters may appear, and if combined with bleeding, the symptoms of blood blisters may appear. 2. Trauma: such as excessive masturbation or excessive intercourse, leading to genital trauma, can also lead to local bleeding and blisters, thus causing symptoms of blood blisters. 3. allergic cutaneous vasculitis: the main symptom is that vasculitis rash can appear, the rash includes erythema, papules, pustules, pustules, blood blisters, etc., and the patient can be conscious of the symptoms of mild itching, pain, or burning sensation. It can be accompanied by fever, joint swelling and pain, myalgia, general malaise and other symptoms. Male genitals appear blood blisters, it is recommended that the patient timely to the hospital, to clarify the cause of the disease, the cause of treatment.