Understanding Acute Febrile Illness Causes
Explore the common causes of Acute Febrile Illness (AFI), from viral and bacterial infections like dengue and typhoid to noninfectious factors. Learn to identify symptoms and understand when to seek medical help.
Written by Dr. M L Ezhilarasan
Reviewed by Dr. Shaik Abdul Kalam MD (Physician)
Last updated on 19th Aug, 2025
Fever is one of the most common health concerns, and when it comes on suddenly, it can be alarming. Acute febrile illness (AFI) refers to a sudden onset of fever that lasts for a short duration, typically less than two weeks. While fever itself is not a disease, it is often a sign that your body is fighting an infection or another underlying condition.
In this article, we’ll explore the causes, symptoms, and management of acute febrile illness in simple terms, helping you understand when to seek medical attention and how to take care of yourself or a loved one.
What Causes Acute Febrile Illness?
Acute febrile illness can be triggered by various infections or inflammatory conditions. Some of the most common causes include:
1. Viral Infections
- Common cold & flu (Influenza) – Often accompanied by body aches, cough, and fatigue.
- Dengue, Chikungunya, & Zika – Mosquitoborne illnesses common in tropical regions.
- COVID19 – May cause fever along with respiratory symptoms.
2. Bacterial Infections
- Typhoid fever – Caused by contaminated food/water; leads to prolonged fever.
- Urinary Tract Infections (UTIs) – Can cause fever with burning urination.
- Pneumonia – Fever with cough and breathing difficulty.
- Ear or throat infections (Strep throat, Otitis media) – Common in children.
3. Parasitic Infections
- Malaria – Spread by mosquito bites; causes high fever with chills.
4. Other Causes
- Heatstroke – Due to excessive heat exposure.
- Autoimmune diseases – Like rheumatoid arthritis or lupus.
- Medication side effects – Some drugs may cause fever as a reaction.
Symptoms to Watch For
Fever is the main symptom, but depending on the cause, you may also experience:
- Chills & sweating
- Headache & body aches
- Fatigue & weakness
- Nausea, vomiting, or diarrhea
- Cough, sore throat, or congestion
- Skin rashes (in dengue or measles)
When to Seek Urgent Medical Help?
- High fever (above 103°F or 39.4°C)
- Fever lasting more than 3 days
- Severe headache, stiff neck, or confusion (could indicate meningitis)
- Difficulty breathing or chest pain
- Dehydration (dry mouth, dizziness, reduced urination)
How Is Acute Febrile Illness Diagnosed?
Since fever can be due to many causes, doctors may recommend:
- Blood tests (for infections like dengue, malaria, typhoid)
- Urine tests (to check for UTIs)
- Throat swab or sputum test (for bacterial infections)
- Imaging (Xray/CT scan) – If pneumonia or other complications are suspected.
If you’re unsure about the cause of your fever, consulting a doctor early can help in timely diagnosis and treatment.
Managing Acute Febrile Illness at Home
Most mild fevers can be managed with simple care:
1. Stay Hydrated
- Drink plenty of water, coconut water, or oral rehydration solutions (ORS).
- Avoid caffeine and alcohol, as they can dehydrate you.
2. Rest & Monitor Temperature
- Take adequate rest to help your body recover.
- Use a thermometer to check fever regularly.
3. FeverReducing Medications
- Paracetamol (Acetaminophen) is usually safe for reducing fever.
- Avoid aspirin (especially in children) unless prescribed.
4. Cool Compresses
- Apply a damp cloth on the forehead, armpits, or groin to bring down fever.
5. Eat Light & Nutritious Food
- Opt for soups, khichdi, bananas, and boiled vegetables for easy digestion.
Consult Top Specialists
When to Consult a Doctor?
While most fevers resolve on their own, certain situations require medical attention:
- Persistent fever beyond 3 days
- Severe symptoms (breathing difficulty, rash, seizures)
- Underlying health conditions (diabetes, heart disease, weakened immunity)
- Recent travel to areas with infectious diseases (malaria/dengue zones)
If you’re unsure about your symptoms, Apollo 24|7 offers quick online consultations where you can speak to a doctor from home. You can also book lab tests to diagnose the cause of your fever.
Preventing Acute Febrile Illness
Some fevers can be prevented with simple precautions:
- Wash hands frequently to avoid infections.
- Stay updated on vaccinations (flu, typhoid, COVID19).
- Use mosquito repellents & nets to prevent dengue/malaria.
- Avoid close contact with sick individuals.
- Drink clean, boiled/filtered water to prevent waterborne diseases.
Final Thoughts
Acute febrile illness is usually a sign that your body is fighting an infection. While most cases are mild and resolve with home care, persistent or severe symptoms need medical attention. Listening to your body, staying hydrated, and getting proper rest are key to recovery.
If you’re concerned about your fever or need expert advice, Apollo 24|7 is here to help with easy online doctor consultations and lab test bookings. Stay informed, stay healthy!
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Consult Top Specialists
Dr. Rajib Ghose
General Practitioner
25 Years • MBBS
East Midnapore
VIVEKANANDA SEBA SADAN, East Midnapore
Dr. Mohamed Azeem
General Physician/ Internal Medicine Specialist
2 Years • MBBS,MD(Internal Medicine) CCEBDM
Karaikudi
Apollo Hospitals Karaikudi, Karaikudi
Dr. Thirupathy K S
General Physician/ Internal Medicine Specialist
11 Years • MD
Karaikudi
Apollo Hospitals Karaikudi, Karaikudi
(75+ Patients)
Dr. Nirmal Mathew Alex
General Physician/ Internal Medicine Specialist
17 Years • MBBS, MD(general medicine)
Angamaly
Apollo Hospitals Karukutty, Angamaly
(50+ Patients)
Dr. Vishal Kumar H
General Physician/ Internal Medicine Specialist
8 Years • MBBS, master class in critical care medicine, Advanced Post Graduate Diploma in Non Invasive Cardiology, certificate course in Cardiovascular Disease & Stroke, Certificate course in Common Mental Disorder
Bengaluru
Apollo Clinic, Basavanagudi, Bengaluru
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