What causes a sudden fever in a child who is otherwise normal? What should be done?

Generally, the main causes of sudden fever in children who are otherwise normal include abrupt changes in environmental temperature, post-vaccination reactions, early stages of acute upper respiratory tract infections, infantile emergency rash (exanthema subitum), and acute otitis media. If symptoms occur, it is recommended to seek timely medical treatment at a regular hospital. Detailed explanations are as follows:

1. Sudden Environmental Temperature Changes

When the environmental temperature surrounding a child suddenly rises or drops and clothing adjustments are not made promptly, it can lead to an imbalance in heat dissipation or production, causing sudden fever. The indoor temperature should be adjusted immediately to between 22-26°C. Appropriate layers of loose, breathable clothing should be worn according to the weather. Physical cooling methods such as wiping the forehead, armpits, and other areas with lukewarm water can help reduce body temperature. Encourage the child to drink more warm water to promote heat dissipation.

2. Post-Vaccination Reaction

Following vaccination, the immune system may react to the vaccine components, potentially causing sudden fever, usually within 24 hours after vaccination. Ensure the child rests adequately and avoids strenuous activities. Monitor body temperature closely. If the temperature does not exceed 38.5°C, fever-reducing patches may be used for cooling. If the temperature exceeds 38.5°C, paracetamol suspension drops may be administered under a doctor's guidance to alleviate fever symptoms.

3. Early Stage of Acute Upper Respiratory Tract Infection

Viral or bacterial invasion of the upper respiratory tract may cause mild early infection symptoms, manifesting only as sudden fever, followed later by coughing and nasal congestion. Under a doctor's guidance, medications such as pediatric paracetamol and chlorpheniramine granules, ribavirin granules, or cefaclor dry suspension may be prescribed to combat infection and relieve symptoms. Ensure the child gets adequate sleep and follows a light, easily digestible diet.

4. Infantile Emergency Rash (Exanthema Subitum)

Caused by human herpesvirus type 6 infection, this condition initially presents without obvious symptoms, only sudden high fever, followed by a rash after the fever subsides. During the fever phase, monitor body temperature closely. Under a doctor's guidance, medications such as ibuprofen suspension, paracetamol suppositories, or pediatric Chaihu Guizhi Tui Re granules may be used to reduce fever. Encourage the child to drink plenty of warm water and avoid crowded places to prevent cross-infection.

5. Acute Otitis Media

Bacterial infection in the ear may cause acute otitis media, which may initially present without obvious symptoms such as ear pain, manifesting only as sudden fever. Under a doctor's guidance, medications such as amoxicillin-clavulanate potassium dry suspension, cefixime granules, or ofloxacin ear drops may be used to combat infection and relieve inflammation. If the eardrum perforation does not heal over a long period, a tympanoplasty (eardrum repair) may be necessary. Prevent water from entering the child's ears to reduce the risk of worsening infection.

In daily life, it is important to pay attention to weather changes and adjust the child's clothing accordingly; closely observe the child's condition within 24 hours after vaccination; maintain good indoor air circulation to reduce the child's exposure to pathogens; when the child suddenly develops a fever, closely monitor their mental state, and seek immediate medical attention if the high fever persists.