The isolation period for scarlet fever is 7 days, or the patient’s symptoms of fever, sore throat, and rash completely disappear, and 3 negative throat swabs are taken before the patient can be released from isolation. Scarlet fever is a respiratory disease caused by group A hemolytic streptococcal infection with an acute onset of fever, sore throat, and diffuse congestive rash. Patients should be isolated at home or in the hospital for 1 week, or if the throat swab culture is negative for 3 times and the symptoms of fever, sore throat and rash disappear completely, the patient is no longer infectious and can be released from medical isolation. If the pharyngeal swab culture continues to be positive, the duration of medical isolation should be extended. Mild cases can be treated with penicillin and cephalosporins, while severe cases require hospitalization. In conclusion, after a patient is diagnosed with scarlet fever, he or she needs to be medically isolated immediately to avoid infecting others.