Red and swollen eyes in children can be conjunctivitis or mydriasis. The common types of conjunctivitis that cause redness and swelling of the eyes in children are allergic conjunctivitis and bacterial conjunctivitis. In patients with allergic conjunctivitis, in addition to redness and swelling of the eyes, they often have itchy eyes, no ocular discharge or mucousy watery discharge, the discharge may even be stretched into filaments, follicular hyperplasia or even giant papillae in the lid conjunctiva, more eosinophils in the conjunctival scrapings, and elevated IgE levels in the serum and tear fluid. In patients with bacterial conjunctivitis, in addition to redness and swelling of the eyes, there is a high level of yellow purulent discharge, and bacterial culture of the discharge usually detects pathogenic bacteria. In patients with mydriasis, in addition to redness and swelling of the eyes, there is localized pain, burning sensation, and localized bulging of the eyelids or pustules. For allergic conjunctivitis, contact with allergens should be avoided, anti-allergic eye drops should be given, and if the allergic reaction is severe, systemic anti-allergic treatment may be given. For bacterial conjunctivitis, antibiotic eye drops can be given empirically. If the results are not good, bacterial culture of ocular secretions should be done, and sensitive antibiotic eye drops should be used according to the drug sensitivity results. For mydriasis, antibiotic eye drops and ointment can be given for treatment, and oral or intravenous antibiotics can be given for severe cases, and if an abscess is formed, surgical incision can be made to drain the pus. In short, conjunctivitis, wheals and other diseases can lead to redness and swelling of children’s eyes, they should go to the eye examination, clear diagnosis, and then give targeted.