Erysipelas, also known as infantile rose rash, is a common rash in infancy and early childhood characterized by a high fever that lasts for 3-5 days and a rash that resolves when the fever subsides. Human herpes virus type 6 (HHV-6) is the most common virus that causes rash in young children. Human herpes virus type 7 (HHV-7), enterovirus, adenovirus, and parainfluenza virus can also cause rash in young children. It often causes infection in children 6 months to 2 years of age, and 95% of children are infected by age 2. The rash is characterized by a sudden onset of the disease and is characterized by a high fever at the beginning of the illness, with a temperature of 39-40°C, which lasts 3-5 days (average 3.8 days) and then drops abruptly, with the rash emerging after the fever subsides. During the fever, the appetite is still good, and the pharynx is congested. The rash appears within 9-12 hours after the fever subsides. The rash is a red macular rash or maculopapular rash, mainly scattered on the trunk, neck, and upper and lower extremities, with a 3-5 mm gap between the rashes, and children do not feel itchy. There are many other diseases that have both fever and rash, such as measles, rubella, enterovirus infections, and even vaccinations, and older children need to be identified as having scarlet fever. Fever: The incubation period is about 1 to 2 weeks, with an average of 10 days. There is a sudden onset of high fever with no prodromal symptoms and a body temperature of 39°C to 40°C or more. In addition to changes in appetite, there is generally no significant change in mental status, but a few children have nausea, vomiting, cough, sclerositis and other symptoms. Rash: After 3 to 5 days of fever, the fever suddenly decreases and the body temperature drops to normal within 24 hours, and the rash appears at the same time or later when the fever subsides. The rash usually occurs first on the face, neck and trunk, and then gradually spreads to the proximal extremities. The rash lasts 1 to 2 days and then subsides without leaving any trace of flaking or hyperpigmentation. Other symptoms include eyelid edema, bulging fontanelle, runny nose, diarrhea, and loss of appetite. Some children have enlarged lymph nodes in the neck. Examination The main basis for determining the diagnosis is the detection of serum anti-HHV-6 and anti-HHV-7 antibodies, and viral DNA can also be detected by viral isolation or PCR (polymerase chain reaction). 1. Routine blood tests On day 1 to 2 of the disease, the white blood cell count may increase, but after the onset of the rash, it decreases significantly, while the lymphocyte count increases, up to 90% or more. Virological tests: virus isolation, detection of virus antigens, determination of virus antibodies, and detection of virus nucleic acid. 3.Other auxiliary examinations No special examination is needed in general cases, but X-ray chest X-ray and electrocardiogram can be done if necessary.