A fever is a temporary rise in body temperature, usually a sign that the body is fighting an infection. Most fevers are self-limiting, but high or persistent fevers require medical evaluation.
A fever is generally defined as a body temperature above 38Ā°C (100.4Ā°F). It is one of the body's natural immune responses, signalling that white blood cells are actively fighting an infection or foreign substance. Normal body temperature ranges from 36.1Ā°C to 37.2Ā°C, though this varies slightly between individuals and throughout the day.
In Korea, fever is commonly caused by upper respiratory tract infections, urinary tract infections, seasonal influenza, food-borne illness, and, particularly in summer, heat exhaustion during heatwaves. Children in Korea frequently develop fevers from viral infections, especially in school and daycare settings.
Most mild to moderate fevers in adults (38Ā°Cā39Ā°C) can be managed at home with rest, adequate fluids, and appropriate fever-reducing medicines such as paracetamol. However, very high fevers, prolonged fevers, or fever in infants and young children should always be assessed by a healthcare professional.
Key Points
- Mild fever: 38ā38.9Ā°C ā monitor symptoms, rest and hydrate
- Moderate fever: 39ā39.9Ā°C ā consider paracetamol, monitor closely
- High fever: 40Ā°C and above ā seek medical attention
- Fever with shaking chills, rapid breathing, or rash may indicate serious infection
- In infants under 3 months, ANY fever above 38Ā°C is a medical emergency
- Fever from heat stroke is different ā skin may be hot but dry rather than sweaty
Causes & Risk Factors
- Viral infections (flu, COVID-19, common cold)
- Bacterial infections (strep throat, UTI, pneumonia)
- Seasonal influenza ā peaks in Korea's winter months
- Food poisoning
- Heat exhaustion or heat stroke during summer heatwaves
- Post-vaccination reaction (normal and expected)
- Inflammatory conditions or autoimmune disease
When to See a Doctor
- Temperature above 40Ā°C in adults
- Any fever in an infant under 3 months (emergency ā call 119)
- Fever lasting more than 3 days
- Fever with severe headache, stiff neck, rash, or difficulty breathing
- Fever with confusion, seizures, or loss of consciousness
- Fever with severe abdominal pain or vomiting
For emergencies in Korea, call 119
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This content is published for educational purposes only. For accurate diagnosis and personalised treatment, consult a licensed KMA physician in Korea.
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Medical Disclaimer
This article is published by DoctorsInKorea.com for educational and informational purposes only. It does not replace a professional clinical evaluation by a licensed healthcare provider. For accurate medical diagnosis and personalised treatment paths, please book an appointment with a licensed KMA physician. For immediate life-threatening medical emergencies in Korea, please call 119.
Sources & References
- NHS UK
- Mayo Clinic
- Korea Disease Control and Prevention Agency
- Korea Ministry of Health and Welfare
- MedlinePlus (NIH)
Last reviewed: May 29, 2026