Spring is bright and it is a good time to walk in the spring. But the dust, willow and pollen flying in the wind are inhaled by many babies, leading to allergic dermatitis, allergic rhinitis, and even acute asthma attacks. Spring is also the season for infectious diseases such as measles and hand, foot and mouth disease. In the pediatric emergency department, we often meet parents who rush into the clinic, “Doctor, does my baby have measles?” The doctor said, “Doctor, what is my baby’s skin bumps?” …… Allergic babies are susceptible to illnesses in spring, especially when they have a cold or fever, and are easily confused with rash infections. Therefore, a brief introduction of several common allergic dermatitis and rash diseases is expected to provide readers with some medical science knowledge. 1, allergic dermatitis Baby skin allergies usually manifest as large red bumps on the body and face, puffy eyelids, scratchy skin, and sometimes even itchy scalp. The enhanced ultraviolet rays of the sun in spring can easily induce solar dermatitis, which manifests as flaking, itching and other symptoms, as well as erythema, papules and scales. Allergic factors such as pollen, dust or mites that babies inhale into the air can induce eczema, producing an itchy local rash that often makes babies irritable, crying and difficult to sleep. Preventive measures: Eat a light diet, balanced nutrition, and plenty of fresh vegetables and vitamin-rich foods. Allergic children should reduce sun exposure, less exposure to flowers, and avoid contact with allergens. Children can take oral anti-allergy drugs and topical ointments, and more serious conditions require timely hospital consultation. There are many causes of skin rashes in babies, such as rubella, chicken pox, scarlet fever, measles, and toddler’s emergency rash. Doctors often diagnose diseases based on the relationship between fever and skin rash and the characteristics of systemic symptoms. Rubella: Rubella virus infection causes a rash that appears half a day to one day after the onset of fever. The red papular rash spreads from the face to the trunk and extremities, without hyperpigmentation or flaking after the rash subsides. Systemic symptoms are mild, with large and tender lymph nodes behind the ear or in the occipital area. Varicella: Varicella zoster virus infection causes a rash that can appear on the first day of fever. Various forms of rash (maculopapular or papular rash, blisters or blisters breaking up, crusting) may coexist. The rash starts on the trunk and gradually extends to the face and extremities, with a blistering rash seen between the hairs. There may be complications such as encephalitis, myocarditis, and facial paralysis. Scarlet fever: caused by Streptococcus hemolyticus B infection, the rash appears on the first 1-2 days of fever. The skin is dense with pinpoint-sized red papules, and the rash recedes after 2-3 days with large patches of peeling skin. The symptoms of poisoning are severe, and a prune tongue and a pale ring around the mouth are visible. Often complicated by pharyngitis,, tonsillitis. Measles: measles virus infection caused by a rash that appears on the 3rd-4th day of fever. May be seen as respiratory cata symptoms, conjunctivitis, oral mucosal spots. Red papules are seen from behind the ears and neck to the trunk and extremities, with hyperpigmentation and desquamation after the rash recedes. The rash period is the peak of body temperature, systemic symptoms aggravated, often complicated by pneumonia, laryngitis, myocarditis, encephalitis, etc. Emergency rash: caused by human herpes virus type 6 infection, the rash appears on the fourth day of fever. The rash appears as red papules, mostly on the neck and trunk, and is complete one day and fades the next, without flaking or pigmentation. There may be convulsions in high fever. Hand-foot-mouth disease: caused by enterovirus infection, fever and rash are not correspondingly related, manifested as fever and rash or herpes on the hands, feet, mouth, buttocks and other parts of the body, most patients are mild. The majority of patients have a mild illness. A small number of seriously ill children may suffer from complications such as myocarditis, pulmonary edema and encephalitis. Due to the rapid development of the disease, it can lead to death. There are more than 20 types of enteroviruses that cause HFMD, including coxsackievirus group A, enterovirus 71, etc. Prevention and treatment measures: Early childhood care institutions and parents who find children with rashes, suspected rash infections should be immediately respiratory isolation, such as measles, the isolation period is 5 days after the rash, extended to 10 days after the rash when complicating pneumonia. And promptly go to a medical institution to take further preventive and control measures. Mildly ill children do not need to be hospitalized, but can be treated at home and bed rest to avoid cross-infection. At the same time, give symptomatic treatment such as antipyretic, expectorant and cough suppressant, sedation, etc., and take vitamins and easily digestible nutrient-rich food orally to facilitate the recovery of the disease. Pay attention to the changes of the child’s condition, if there is poor mental response, frequent vomiting, high fever persists, etc., it is necessary to promptly go to the hospital for treatment. The main measure to prevent infectious diseases is to develop good hygiene habits, “wash hands often, open windows regularly, drink boiled water, eat cooked food, and dry clothes and blankets.