A white blister on the edge of the anus may be caused by herpes simplex, skin allergies, perianal abscesses, etc. Patients should consult a doctor in time to clarify the cause of the disease and then carry out appropriate treatment. 1. Herpes simplex: herpes simplex virus infection caused by a skin disease, the site of infection can be perianal, the patient will have localized blisters, pain, burning sensation, and general weakness, poor appetite and other symptoms, such people should pay attention to the local skin care, local use of glycerine lotion, acyclovir cream and other drugs when necessary. 2. Skin allergy: If before the occurrence of white blisters on the edge of the anus, the patient has been in contact with animal fur, pollen and other substances, and there are white blisters on other parts of the body, it should be considered to be allergy-induced, such people should avoid re-exposure to allergens, the use of loratadine and other drugs for treatment. 3. Perianal abscess: there is a white blister on the edge of the anus may also be a perianal abscess, is due to the formation of perianal tissue infected by bacteria and suppurative infections, there will be persistent pain in the perianal area, fever, acute and severe symptoms, antibiotics can be used for treatment, if necessary, can be incised and drainage of the abscess. It is recommended that when the patient has a white blister on the edge of the anus, he should go to the hospital in time to clarify the cause of the disease and give treatment as soon as possible to avoid aggravation of the condition. All of the above drugs and treatments should be carried out under the guidance of a doctor.