If the baby’s skin turns purple only during fever, it is considered to be related to sympathetic excitation, skin vasoconstriction, reduced superficial blood flow and poor circulation of body fluids during fever, and physical and medication can be given to reduce heat treatment symptomatically. The common cause of fever is infection, various pathogens such as viruses, bacteria, mycoplasma, chlamydia, rickettsia, etc. cause fever. If your baby’s fever does not subside even after giving general medication, it is recommended to go to the hospital for blood tests and other infection indicators to clarify the cause of the fever and further develop a treatment plan. Non-infectious diseases can also cause fever, such as blood diseases, connective tissue diseases, allergic diseases, as well as endocrine metabolic diseases, malignant tumors, physical and chemical damage, etc. If the baby’s skin remains purple after the fever subsides, further investigation of the hematological system and heart is also required.