Feber

Feber, or fever, is a temporary increase in body temperature above the normal range. Normal body temperature varies with age, activity, and measurement method; a common threshold for fever is a body temperature above 38.0 C (100.4 F) when measured orally. Rectal measurements are usually slightly higher, while axillary readings may be lower.

Most fevers are caused by infections, particularly viral or bacterial illnesses. Other factors can include inflammatory or autoimmune diseases, certain cancers, heat-related illness, medications or drug reactions, and postoperative states. Fever is part of the body’s immune response: pyrogens stimulate the hypothalamus to raise the body’s temperature set point, leading to heat production and retention (shivering and vasoconstriction) until the new set point is reached.

Symptoms commonly accompanying fever include chills, fatigue, headache, and sweating. As the temperature changes, patients may experience warmth or flushed skin and reduced appetite. Evaluation is guided by age, illness presentation, and red flags. Persistent fever, very high temperatures, or fever with symptoms such as severe headache, stiff neck, confusion, severe dehydration, persistent vomiting, or signs of septic shock warrants medical assessment. Fever lasting several weeks without a clear source is termed fever of unknown origin and requires further investigation.

Management focuses on addressing the underlying cause and relieving symptoms. Antipyretics such as acetaminophen (paracetamol) or nonsteroidal anti-inflammatory drugs can reduce fever and discomfort. Adequate fluids and rest are advised. Aspirin should be avoided in children and teenagers due to the risk of Reye’s syndrome. Special consideration is given to vulnerable groups, including infants, the elderly, and immunocompromised individuals, who may require prompt medical evaluation.