A mild rash after MMR vaccination can be left untreated for the time being. When the rash is severe, it is recommended to take desensitizing medication such as loratadine under the guidance of a doctor, and glycerine lotion can be used to stop the itching. MMR vaccine is suitable for the prevention of measles, mumps, rubella virus infection of the combined vaccine, after the vaccination of MMR vaccine, the body may appear scattered rash and other adverse reactions. When the rash is mild, it is only scattered rash without obvious redness, swelling and pain, then it can be left untreated for the time being, and the mild rash can subside within a few days. If the rash situation is more serious, the body more parts of the rash, the color of the rash is bright red, there is obvious redness, swelling and pain, itching, etc. need to consult a doctor as soon as possible, do not rule out allergic reactions, can be taken under the guidance of a doctor, such as loratadine, desensitizing medication, itching is serious can be wiped with glycerite lotion.