Blister in medicine refers to a blister. Blistering of the skin may be caused by diseases such as herpes zoster, contact dermatitis and ringworm. 1. Herpes zoster: the cause is mainly related to chickenpox-herpes zoster infection. Patients will have localized pain, blisters, papules and other symptoms, which can be seen in any part of the body, usually unilateral limb involvement. 2. Contact dermatitis: the etiology is mainly related to the allergic reaction caused by skin contact with exogenous substances such as lacquer and leather. Patients will appear localized erythema, blisters, papules and other symptoms. 3. Ringworm: the cause of the disease is mainly related to the skin ringworm bacterial infection. The main manifestations are papules, blisters, papules and scaly erythema. If the skin blisters appear, it is recommended to go to the regular hospital for examination to clarify the cause of the disease.