Rubella is not an infectious disease, but are problems with the skin of patients with rubella, often bringing great physical and mental pain and economic burden to the patient, the main two causes of triggering rubella are as follows: a. Infection factors: Local infection is an important cause of triggering rubella, especially after a cold, complicated by tonsillitis, bronchitis, need to be actively treated to minimize the duration of the disease. Tonsillectomy can be considered for those with recurrent tonsil inflammation, which is closely related to the onset of urticaria, and this is especially important for adolescent patients. Second, allergic factors: skin allergy is one of the main reasons for triggering rash. Allergies due to diet or medication, or exposure to a substance can often trigger the onset of rash. After each relapse, patients need to carefully recall what they have taken or touched in the recent past, thus making the skin itchy, followed by erythema symptoms, and should try to avoid contact in the future, such as certain seafood, beef and mutton, spicy food and other substances.