A fever or pyrexia is a rise in body temperature above normal and often indicates an illness. Average normal body temperature is 98.6oF but it can range between 97 and 99.5oF. Body temperature varies according to time of the day, exercise, ambient temperature and site of measurement. Body temperature is higher in the evening than in the morning and higher when measured under the tongue compared to armpit. Women during menstruation also have higher body temperature. Fever is body’s normal reaction to infection and other stressful conditions and has a protective effect on body’s ability to fight infection. Hence, trying to reduce temperature down too early may not always be beneficial. However, when the temperature rises above 102 degree F, it is concerning and should be treated with antipyretics. Very high fever can cause seizures in children.
Fever is symptom of an underlying disease. Pyrogens (chemicals that cause fever) produced in response to infectious (bacteria, virus, fungus, parasite), immunologic, neoplastic (cancer) or other stimuli reach the brain and alter temperature regulation causing fever.
- Respiratory tract infections: Examples- Cold or flu -like illnesses, sore throat, sinusitis, laryngitis, epiglottitis, bronchitis, pneumonia, tuberculosis, measles, chicken pox. Infections of the middle ear (otitis media)
- Gastrointestinal tract infection: Viral and bacterial gastroenteritis such as diarrhea, dysentery. Typhoid fever , Hepatitis, ulcerative colitis, appendicitis, peritonitis .
- Urinary tract infections e.g. infection of urinary bladder (cystitis), urethra, kidney (pyelonephritis)
- Bone infection: osteomyelitis
- Skin infections or cellulitis
- Central nervous system: meningitis- infection of the meninges (membrane covering the brain), encephalitis
- Infections affecting immune system: Human immunodeficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDS).
- Infection of red blood cells (Malaria), or internal organs (Kala-azar or Leishmaniasis)
- Abscess (collection of pus) in any part of the body.
- Autoimmune conditions:
- Connective tissue diseases such as Rheumatoid Arthritis and Systemic Lupus Erythematosus
- Endocrine causes like hyperthyroidism (overactive thyroid gland)
- Cancers: Fever may be early sign of blood cancer (leukemia, lymphoma). Other cancers may cause fever in when they affect immune system or spread to other organs.
- Drugs: Antimicrobials (sulfa, penicillin), antiepileptics (phenytoin), antihypertensives (Hydralazine, Methyldopa) and others drugs have potential to cause fever.
- Provide plenty of fluids to drink, and monitor if person is making urine.
- Put on only necessary clothes
- Maintain cross ventilation in the room
- Cold sponging on forehead, armpits and groins or any other parts of the body.
- Provide oral paracetamol if temperature is not reduced with above mentioned remedies.
Fever doesn’t always need treatment as this is our body’s protective mechanism to fight the infection. When fever is very high, antipyretics such as paracetamol, ibuprofen are used to bring the temperature down. However, they do not cure the underlying disease. Most viral illnesses are self limiting while other causes of infection require specific therapy with antibiotics, antifungals and antiparasitic drugs. Aspirin should not be given to treat fever in children as this can cause a life threatening condition called Reye’s Syndrome.
When to visit the Doctor
- If the temperature is 102 F (38.9 C) or greater (high grade fever)
- Fever with any of symptoms like- confusion, stiff neck or severe headache, convulsion, difficulty swallowing or breathing, diarrhea, vomiting, burning urination, scanty urination, rash or severe abdomen or back pain.
- Fever after recent surgery or medical procedure.
- Fever in pregnancy
- Fever in person with diseases like diabetes, chronic kidney disease.
- Fever in person taking medicine to suppress immune system (cancer chemotherapy, organ transplant recipient).
- Persistent fever for several days.
- Fever after travel.
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