The causes of itching inside the cast of fracture are non-ventilation affected by sweat, allergy, infection, etc. According to the causes, corresponding treatment should be carried out, such as general treatment, medication and so on. 1. Non-ventilation affected by sweat: if the itching is caused by the skin affected by sweat due to the non-ventilation of the cast, the skin can be cleaned properly and then the cast can be replaced. 2. Allergy: If the itching is caused by allergy due to direct skin contact with the plaster, it can be treated by oral medication or ointment. At the same time, the plaster should be padded with ointment cotton to prevent the patient from direct contact with the plaster. 3. Infection: If it is particularly itchy, it may also be due to localized infection, in this case. You should go to the hospital in time, let the doctor look at the infection, and disinfect the treatment, and then fix the plaster. In addition, wounds in the process of healing will also have symptoms of itching, which is normal. It is recommended that itchy patients should still go to the hospital in time to identify the cause of the disease and follow the doctor’s instructions for treatment.