Fact-checked by MyHSN experts | Updated: May 2026
A fever is more than just a high number on a thermometer; it is your body’s sophisticated defence mechanism
Understanding the triggers and treatments for a high temperature can help you manage your recovery effectively.
In adults, a fever is clinically defined as a body temperature of 38°C (100.4°F) or higher.
While the “average” body temperature is , it is normal for your temperature to fluctuate slightly throughout the day based on activity, hormone levels, and time of day.
Fever is rarely an illness itself; it is a symptom of an underlying issue.
The “Kill Zone”: Raising your internal temperature creates a hostile environment for many bacteria and viruses, slowing their ability to replicate.
Immune Signal: A fever acts as a signal to your immune system to produce more white blood cells.
Note: In the elderly, the absence of a fever during an infection can actually be more concerning, as it may suggest a diminished immune response.
Most fevers are caused by viral or bacterial infections, but there are non-infectious triggers as well.
Infectious Causes
Respiratory: Colds, Flu, COVID-19, Bronchitis, and Pneumonia.
Internal: Urinary Tract Infections (UTIs), Kidney infections, or Gastroenteritis (stomach bugs).
Severe: Meningitis, Cellulitis, or Sepsis (a life-threatening medical emergency).
Non-Infectious Triggers
Autoimmune Disorders: Such as Rheumatoid Arthritis (RA) or Lupus (SLE).
Heat Stroke: Resulting from overexposure to sun or strenuous exercise.
Medications: Certain antibiotics or blood pressure medications.
Genetics: Rare conditions like Familial Mediterranean Fever (FMF).
As your temperature climbs and falls, you will likely experience:
Rigors: Shivering and feeling cold as the body tries to raise its temperature.
Sweating: Feeling flushed and warm as the fever “breaks” and the body tries to cool down.
Dehydration: Increased fluid loss through breath and sweat.
Unless a fever is causing significant discomfort or is dangerously high (above ), it may not need to be suppressed. If you do treat it, focus on comfort:
Hydration: Drink water, broth, or oral rehydration salts to replace lost fluids.
Rest: Allow your energy to go toward fighting the infection.
OTC Medication: Paracetamol or Ibuprofen are effective at reducing fever and associated aches.
Avoid Antibiotic Misuse: Antibiotics treat bacteria, not viruses (like the flu). Overuse contributes to global antibiotic resistance.
While this guide focuses on adults, it is vital to note that children may experience febrile seizures if their temperature rises rapidly. While terrifying for parents, these are usually brief and do not typically cause long-term brain damage or epilepsy.
Seek medical attention immediately if a fever is accompanied by:
A stiff neck and light sensitivity (possible meningitis).
Confusion or delirium.
A rash that does not fade under a glass.
Difficulty breathing.
A temperature that stays above despite medication.
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