Overview
Fever is a temporary elevation of body temperature above the normal range, generally defined as an oral temperature of 38°C (100.4°F) or higher. It is one of the most common reasons for medical consultation in Nigeria and across the world. Fever is not a disease itself but a symptom — a sign that the body's immune system is actively fighting an infection or responding to inflammation. Most fevers are caused by common viral or bacterial infections and resolve on their own within a few days. However, fever can sometimes indicate a serious underlying condition, particularly in very young children and immunocompromised individuals. In Nigeria, fever in any age group should always raise suspicion for malaria until proven otherwise.
Symptoms
The main feature is a raised body temperature, which may be accompanied by:
• Sweating: particularly as the fever breaks
• Shivering and chills: especially as the temperature rises
• Headache
• Muscle aches and joint pains
• Weakness and fatigue
• Loss of appetite
• Dehydration: dry mouth, concentrated urine, reduced urine output
• Flushed, hot skin
In children:
• Irritability and unusual crying
• Difficulty sleeping
• Refusal to eat or drink
• Febrile convulsions: in children aged 6 months to 5 years (more alarming than dangerous in most cases, but requires medical evaluation)
High fever symptoms (above 39.5°C / 103°F):
• Confusion or delirium
• Severe headache
• Stiff neck (suggests meningitis: emergency)
• Sensitivity to light
When to See a Doctor
In adults — seek medical attention for fever if:
• Temperature is 39.5°C (103°F) or higher
• Fever has lasted more than 3 days
• Fever is accompanied by severe headache, stiff neck, or sensitivity to light: possible meningitis
• You have chest pain, difficulty breathing, or rapid breathing
• You have confusion, severe drowsiness, or difficulty waking
• You develop a new rash alongside fever
• You have been in an area with known disease outbreaks (cholera, Lassa fever, meningitis)
• You have a weakened immune system (HIV, chemotherapy, diabetes)
In children — seek medical attention immediately if:
• Any fever in a baby under 3 months (even 38°C should be evaluated)
• Fever above 38.5°C in babies aged 3–6 months
• Fever has lasted more than 5 days in a child of any age
• The child has a convulsion (febrile seizure)
• The child cannot be roused, is unusually drowsy, or has difficulty breathing
• The child has a non-blanching rash (rash that does not turn white when pressed)
In Nigeria: Test for malaria in any person with fever — do not treat blindly without testing.
Causes
The most common causes of fever in Nigeria include:
Infectious causes (most common):
• Malaria: must be excluded in any fever in Nigeria
• Upper respiratory tract infections: common cold, throat infections, sinusitis
• Influenza (flu)
• Typhoid fever: especially with sustained fever lasting over a week
• Urinary tract infection (UTI)
• Pneumonia
• Meningitis (high fever with stiff neck: emergency)
• Tuberculosis: causes a chronic, low-grade fever with night sweats and weight loss
• Viral hepatitis
• HIV: fever is common during primary infection
• Lassa fever: in endemic areas (Edo, Ondo, Bauchi, Plateau states and surroundings)
Non-infectious causes:
• Inflammatory conditions (rheumatoid arthritis, lupus)
• Certain cancers (lymphoma, leukaemia)
• Some medications (drug fever)
• Heat stroke (hyperthermia): very high temperature without true fever; life-threatening
Risk Factors
• Young age: infants and children have immature immune systems and are more susceptible to infections
• Living in areas with high malaria transmission
• Lack of vaccination (measles, typhoid, meningococcal disease increase risk of febrile illness)
• Weakened immune system
• Poor sanitation and hygiene
• Crowded living conditions
• Recent travel to high-risk areas
• Working in healthcare settings
Complications
• Febrile convulsions (febrile seizures): occur in 2–5% of children aged 6 months to 5 years; alarming but rarely cause lasting harm; however, the underlying cause of fever still requires evaluation
• Severe dehydration: from sweating and reduced fluid intake; especially dangerous in infants and the elderly
• Delirium and confusion in elderly patients
• The underlying cause progressing: untreated malaria becoming severe malaria; pneumonia worsening; meningitis causing brain damage
• Hyperthermia (heat stroke): if not genuine fever but heat illness, can be fatal without rapid cooling
Prevention
Since fever is a symptom and not a disease, preventing it means preventing its underlying causes:
• Sleep under a mosquito net and use repellents to prevent malaria
• Drink clean, treated water to prevent typhoid and other waterborne illnesses
• Wash hands frequently to prevent respiratory and gastrointestinal infections
• Stay up to date with vaccinations: meningococcal vaccine, influenza vaccine, pneumococcal vaccine
• Maintain good nutrition and overall health to support immune function
For fever management at home:
• Give paracetamol (acetaminophen) at the correct dose for age and weight to reduce fever and relieve discomfort
• Ensure adequate fluid intake (oral rehydration solution or clean water)
• Do not bundle children in heavy clothing: light, breathable clothing helps the body cool
• Sponging with lukewarm (not cold) water can help
• Do not use aspirin in children under 12: associated with Reye syndrome