Common Causes of Recurring Fever in Adults

Are you suffering from a fever but don't know the cause? Well, it's not just you; people are often confused about understanding the cause of fever. It could be an infection, bacterial, viral, or other health issue.

But why does fever come? 

Fever is the body's natural way of fighting off infections and inflammation. It's common to get a fever occasionally when you catch a cold, flu, or any short-term illness. But when a fever keeps returning, it can signify something more serious. This is known as recurring fever, which means your body has issues that haven't been fully resolved.

Recurring fevers can occur in adults for many reasons. They may be caused by viral or bacterial infection, a chronic illness, or even an autoimmune condition where the body mistakenly attacks itself. Sometimes, a fever can be a side effect of medication; it may be tuberculosis or cancer.

However, it's essential to understand how frequently the fever occurs, how long it lasts, and what other symptoms accompany it, such as fatigue, pain, night sweats, or weight loss.

In this blog, let's explore the most common causes of recurring fever in adults, how to identify them, and what to do if you experience repeated fevers.

Common Causes of Recurring Fever in Adults

Let’s understand the possible causes of recurring fever in adults.

1. Viral Infections

Some viruses take longer to clear from the body and may cause fever over days or weeks.

• Examples: Epstein-Barr virus (EBV), cytomegalovirus (CMV), dengue, and COVID-19
• Symptoms: Fatigue, sore throat, swollen glands, muscle aches

Viral fevers resolve without antibiotics but may take time to recover if you have weak immunity.

2. Bacterial Infections

Bacterial infections can also cause high fevers, which may return until the infection is completely treated.

• Examples: Tuberculosis, urinary tract infections (UTIs), sinusitis, pneumonia, abscesses
• Symptoms: Chills, fatigue, pain or swelling, sometimes pus or discharge

These bacterial infections require antibiotic treatment. If the fever is not recovered well or the treatment is improper, it may cause a recurrence.

3. Chronic Inflammatory or Autoimmune Diseases

Some diseases may cause inflammation in the body and can trigger regular fever.

• Examples: Lupus, rheumatoid arthritis, inflammatory bowel disease (IBD)
• Symptoms: Joint pain, skin rashes, digestive problems, fatigue

If you are suspected of inflammation or autoimmune disease, get properly diagnosed through blood and imaging tests and receive proper treatment.

4. Cancer and Blood Disorders

Some types of cancer and blood conditions can also cause on-and-off fever.

• Examples: Leukemia, lymphoma, multiple myeloma
• Symptoms: Sudden weight loss, night sweats, swollen lymph nodes, constant fatigue

If you are not feeling relieved, it might be due to a serious issue. Fever may be the first symptom of some cancers and needs a thorough evaluation.

5. Tuberculosis (TB)

TB is a major cause of recurring fever. To be treated properly, it requires a long course of antibiotics, lasting six months or more.

• Symptoms: Night sweats, weight loss, cough with or without blood, fatigue
• Diagnosis: Chest X-ray, sputum test, TB blood test

6. Malaria and Dengue

Dengue and malaria are other causes of fever that may lead to recurring fevers.

• Symptoms of Malaria: Chills, sweating, headaches, vomiting, fever at regular intervals
• Symptoms of Dengue: High fever, joint/muscle pain, rash, bleeding gums

Consult your healthcare provider, and take blood tests for malaria and Dengue to confirm the diagnosis and start treatment early.

7. Medication-Induced Fever

Certain medications can cause fever as a side effect.

• Common causes: Antibiotics (like penicillin), anti-seizure meds, blood pressure meds
• Always inform your doctor about all medications and supplements you are taking.

8. Post-Vaccination Fever

If you have recently been vaccinated and are experiencing a fever, don't worry; it's a common side effect. Some people experience a low-grade, recurring fever after receiving certain vaccines. The fever is usually mild and goes away without treatment.

• Common with: COVID-19 vaccine, flu shots, hepatitis vaccines

9. Poorly Managed Chronic Conditions

If you have health conditions such as diabetes or kidney disease, it may weaken your immunity and increase your susceptibility to recurring infections.

Read more: How to Know What’s Causing Your Fever: Dengue, Typhoid, or Viral?

Fever in adults: When to worry

Recurring fever isn’t something you should ignore. Seek medical help if you experience:

• Fever over 103°F (39.4°C)
• Fever lasting more than 3 days
• Night sweats or weight loss
• Persistent cough or breathlessness
• Pain, swelling, or discharge anywhere in the body
• Symptoms that keep coming back despite treatment

Blood Tests To Diagnose Recurring Fever in Adults

To find the cause of recurring fever, your doctor may recommend:

• Complete Blood Count (CBC)
• ESR & CRP test
• Liver and kidney function tests
• Urine and blood cultures
• WIDAL Test
• Malaria and dengue tests

Other important tests and scans

• Chest X-ray or CT scan

Also read: Get a Fever Test at Home: Booking, Collection & Report Process

Treatment Options

Treatment of recurring fever depends on the cause of the fever. Fever is a symptom, not a disease. The key is to treat the root issue, not just the fever. Here are the common treatment options based on the cause:

1. Viral Infections

Treatment includes:

• Rest and hydration
• Fever-reducing medication like paracetamol (acetaminophen) or ibuprofen
• Nutritious diet to support immunity
• Isolation if the virus is contagious (e.g., COVID-19, flu)

2. Bacterial Infections

Treatment includes:

• A full course of antibiotics specific to the infection (e.g., UTI, pneumonia, sinusitis)

3. Autoimmune or Inflammatory Disorders

Treatment includes:

• Corticosteroids (e.g., prednisone) to reduce inflammation
• Immunosuppressive drugs (e.g., methotrexate)
• Lifestyle changes to reduce flare-ups

4. Malaria & Dengue

Malaria Treatment:

• Antimalarial drugs like artemisinin-based combination therapy (ACT)

Dengue Treatment:

• No specific antiviral, but supportive care includes:
• Hydration
• Pain relief (avoid aspirin)
• Monitoring platelet levels

5. Medication-Induced Fever

• Identify the drug
• Stop it (with the doctor's approval)
• Monitor for improvement
• Consider alternatives

6. Supportive Home Care (for mild cases)

• Drink plenty of water and oral rehydration solutions (ORS)
• Use cold compresses to lower body temperature
• Eat light, easy-to-digest foods like soups and fruits

Always consult a doctor if:

• Fever lasts more than 3 days
• You experience weight loss, night sweats, or severe fatigue
• You have health conditions like diabetes, heart disease, or cancer

Also read: How to Treat Fever Naturally: 8 Home Remedies For Fever

Prevention tips for fever

Here are some effective tips to help prevent fever and the illnesses that cause it:

• Wash your hands regularly with soap and water. 
• Use hand sanitizer when soap isn’t available.
• Avoid touching your face, like your eyes, nose, and mouth.
• Get vaccinated against common fever-causing illnesses, including influenza (flu), COVID-19, Hepatitis, Typhoid, Measles, and mumps.
• Consume fruits, vegetables, and 
• foods rich in vitamin C, zinc, and iron to boost immunity.
• Drink plenty of water. 
• Aim for 7–9 hours of sleep each night.
• Avoid contact with people who are coughing, sneezing, or visibly ill.
• Wear a mask in crowded places.
• Disinfect commonly touched surfaces, such as doorknobs, switches, and phones.
• Regular check-ups and proper medication help reduce the risk of infection.

Final Thoughts

Fever is your body’s way of telling you that something is wrong in the body. When it happens repeatedly, it’s a sign that your body may be fighting a long-term infection, inflammation, or another hidden issue. 

The good news is that many of the causes of fever can be diagnosed and treated properly. 

Your health is in your hands; listen to your body, and don't wait too long to seek help when something feels off. It's always better to be safe and protect yourself. Stay healthy, and take care of yourself!

FAQ’s

1. What are the five main causes of fever?

The 5 main causes of fever are infection (viral or bacterial), inflammation, drug reactions, autoimmune disorders, and cancer.

2. What is the main cause of frequent fever?

Frequent fever, also known as recurrent fever, can be caused by various factors, including infections, autoimmune disorders, and certain genetic conditions.

3. What are the most common fevers?

Viral or bacterial infections are the most common cause of fevers.

4. What causes fever in adults?

Fevers are most commonly caused by viral and bacterial infections in adults. Other causes include inflammatory conditions, drug reactions, autoimmune disorders, and, in some cases, cancers. 

5. When to worry about a fever?

A fever of 103°F (39.4°C) or higher in adults needs immediate medical attention. If fever is accompanied by other symptoms, such as difficulty breathing and persistent vomiting, it also requires medical attention.