Two-year-old baby fever well with a red rash, may be drug rash, toddler emergency rash and other factors caused. 1. Drug rash: drugs enter the body through oral, injection, inhalation and other ways. If you are allergic to the ingredients inside the drug, it can cause an allergic reaction, resulting in skin erythema, acne, papules, vesicles, oozing, itching and other manifestations. It is recommended to stop the use of suspected allergy-causing drugs, and give diclofenac tadalafil, cetirizine hydrochloride and other drugs to treat. 2. Acute rash in young children: Acute rash in young children is a common viral infection in infants and young children, and the cause of the disease is relatively clear, which is related to human herpesvirus type VI infection. The main manifestation of infantile rash is fever at the beginning, and the rash may appear after the body temperature is normalized, and the rash usually lasts for 1-2 days and then gradually subsides, so it does not need any special treatment. After the fever is over, it is recommended to go to the dermatology and pediatrics department of the hospital for examination and symptomatic treatment under the guidance of the doctor.