What causes recurrent fevers at night?

A person's body temperature naturally fluctuates throughout the day due to circadian rhythms, often peaking in the evening. This natural cycle can intensify when an underlying condition is present, leading to the frustrating question: What causes recurrent fevers at night?

Quick Summary

Recurrent fevers at night can be triggered by infections, autoimmune disorders, or genetic periodic fever syndromes. They are often amplified by the body's natural circadian rhythm and an immune response that intensifies during evening hours. Consultation with a doctor is essential for accurate diagnosis and proper management of the underlying cause.

Key Points

• Circadian Rhythm: The body's internal clock naturally raises temperature and immune activity at night, amplifying fever symptoms.

• Hidden Infections: Chronic or occult infections like tuberculosis or endocarditis can be a source of persistent nighttime fevers.

• Autoimmune Disorders: Conditions such as lupus and rheumatoid arthritis can cause recurrent fevers as part of their inflammatory process.

• Periodic Fever Syndromes: A category of rare genetic conditions that result in unexplained, periodic febrile episodes, often with other inflammatory symptoms.

• Underlying Malignancy: Certain cancers, particularly lymphomas and leukemia, can cause fever and night sweats as a symptom.

The Role of the Circadian Rhythm and Immune Response

Even in healthy individuals, body temperature varies slightly throughout the day, often rising in the afternoon and evening. This is regulated by the hypothalamus, the body's internal thermostat, and is part of the normal circadian rhythm. When the body is fighting an infection or inflammation, the hypothalamus resets its temperature to a higher point, causing a fever.

At night, levels of the anti-inflammatory hormone cortisol drop, allowing the immune system to become more active. This can cause existing fever symptoms to worsen or spike during the evening hours. For those experiencing recurrent fevers, this natural phenomenon can make the underlying problem particularly noticeable during sleep.

Infectious Causes of Recurrent Fevers

Many infections, both common and more severe, can lead to recurrent fevers, especially if they are chronic or difficult to treat. These include:

Viral Infections

• Chronic Viral Infections: Some viruses, like HIV or those causing infectious mononucleosis, can lead to prolonged or recurrent fevers.
• Episodic Viruses: Even common viruses can cause intermittent fevers, especially in young children whose immune systems are still developing.

Bacterial Infections

• Tuberculosis (TB): A classic cause of persistent fever and night sweats.
• Occult Infections: Hidden or untreated infections, such as a deep-seated abscess, infective endocarditis (infection of the heart lining), or chronic urinary tract infections, can cause recurrent febrile episodes.
• Lyme Disease: This tick-borne illness can cause flu-like symptoms, including fever, that can come and go.

Other Infections

• Malaria: If you have recently traveled to a region where malaria is endemic, recurrent fevers are a hallmark symptom.

Autoimmune and Inflammatory Conditions

Systemic inflammation caused by autoimmune diseases can lead to recurrent fevers as the immune system mistakenly attacks healthy tissue.

• Systemic Lupus Erythematosus (Lupus): A chronic inflammatory disease that can affect many different body systems and commonly causes fever during flare-ups.
• Rheumatoid Arthritis: An inflammatory condition of the joints that can also cause systemic symptoms like fever.
• Inflammatory Bowel Disease (IBD): Conditions such as Crohn's disease and ulcerative colitis can cause systemic inflammation and fever, especially during active periods.
• Vasculitis: Inflammation of the blood vessels can result in fever and other systemic symptoms.

Genetic Periodic Fever Syndromes

These are a group of rare, inherited autoinflammatory diseases that cause unprovoked, recurring bouts of fever and inflammation. They are not caused by an outside infection.

• PFAPA Syndrome (Periodic Fever, Aphthous Stomatitis, Pharyngitis, Adenitis): The most common of these syndromes, primarily affecting young children.
• Familial Mediterranean Fever (FMF): Affects individuals of Mediterranean and Middle Eastern descent and can cause fevers with abdominal, chest, or joint pain.
• Tumor Necrosis Factor Receptor-Associated Periodic Syndrome (TRAPS): A genetic disorder causing prolonged, recurring fevers, often with a painful rash.
• Hyperimmunoglobulin D Syndrome (HIDS): A rare genetic condition that often begins in the first year of life with high fevers.

Malignancies and Neoplastic Fever

Some cancers can produce fever, known as neoplastic fever, as a paraneoplastic syndrome, meaning it's a symptom caused by the cancer's effect on the body rather than a direct infection.

• Lymphomas: Both Hodgkin's and non-Hodgkin's lymphoma are known to cause recurrent fevers, often accompanied by night sweats and weight loss.
• Leukemia: Cancers of the blood can lead to recurrent or persistent fevers.
• Renal Cell Carcinoma (Kidney Cancer): Can be associated with fever and other systemic symptoms.

Drug-Induced Fever and Other Factors

Several other causes can lead to recurrent febrile episodes at night, making a thorough medical evaluation crucial.

• Medication Side Effects: Certain drugs, including some antibiotics, antidepressants (SSRIs), and corticosteroids, can cause fever as a side effect.
• Endocrine Disorders: Conditions like hyperthyroidism and nocturnal hypoglycemia (low blood sugar) can cause night sweats and temperature dysregulation.
• Stress and Anxiety: High levels of psychological stress can trigger physiological changes, including intermittent, unexplained fevers.
• Obstructive Sleep Apnea (OSA): Disrupted breathing patterns during sleep can sometimes be associated with night sweats and disturbed body temperature regulation.
• Factitious Fever: A rare but documented cause where a person self-induces fever.

Comparing Periodic Fever Syndromes

Syndrome	Cause	Typical Onset Age	Typical Flare Duration
PFAPA Syndrome	Unknown (autoinflammatory)	2–5 years	3–6 days
Familial Mediterranean Fever (FMF)	Genetic (MEFV gene)	Usually before 10 years	12 hours – 3 days
TRAPS	Genetic (TNFRSF1A gene)	Childhood or early adulthood	Weeks to months

Investigating Recurrent Nighttime Fevers

If you or a family member is experiencing recurrent fevers at night, especially with other symptoms like night sweats, weight loss, or pain, seeking medical attention is vital. The diagnostic process can be complex and may involve multiple steps:

1. Detailed History and Physical Exam: A doctor will review your medical history, recent travel, medications, and other symptoms to look for clues.
2. Blood Tests: These may include a complete blood count (CBC), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) to look for signs of infection, inflammation, or hematological issues.
3. Infection Screening: Your doctor may screen for specific infections, such as tuberculosis or HIV, or perform blood and urine cultures if an infection is suspected.
4. Autoimmune and Genetic Testing: If autoinflammatory or autoimmune diseases are suspected, specific antibody tests or genetic testing may be necessary.
5. Imaging: X-rays, CT scans, or MRIs may be used to look for internal abscesses, tumors, or other sources of inflammation.

The Importance of Professional Medical Advice

Recurrent fevers at night have a wide and complex range of potential causes, from benign viral infections to serious underlying diseases like cancer or autoimmune conditions. A nighttime temperature spike is not always a sign of a serious illness, but its persistence warrants medical investigation to ensure proper diagnosis and treatment. The information provided here is for educational purposes only and is not a substitute for professional medical advice. Always consult a healthcare professional for an accurate diagnosis and treatment plan. Visit the Mayo Clinic for more details on fever causes.

Frequently Asked Questions

Why do fevers get worse at night?

Fevers often spike at night due to the body's natural circadian rhythm. Levels of the anti-inflammatory hormone cortisol drop in the evening, allowing the immune system to become more active and intensify the febrile response.

Can stress cause recurrent fevers at night?

Yes, chronic stress and anxiety can potentially contribute to recurrent fevers. While less common, the link between psychological factors and physiological responses can sometimes trigger unexplained temperature increases.

What is a periodic fever syndrome?

A periodic fever syndrome is a rare genetic disorder characterized by recurring bouts of fever that are not caused by an infection. These autoinflammatory conditions can cause other symptoms like rashes, joint pain, and abdominal issues.

When should I see a doctor for recurrent nighttime fevers?

You should see a doctor if you experience persistent or recurrent fevers, especially if they are accompanied by other symptoms like weight loss, severe sweating, or localized pain. Medical evaluation is crucial to determine the underlying cause.

Can medications cause recurrent fevers?

Yes, a number of medications can cause drug-induced fevers. These include certain antibiotics, corticosteroids, and some blood pressure medications. Reviewing your medication list with a doctor is a key diagnostic step.

Are recurrent night fevers a sign of cancer?

While recurrent fevers can be a symptom of certain cancers, such as lymphoma and leukemia, it is important to remember that many other, less severe conditions can cause them. It's one possible cause among many, and a doctor's evaluation is necessary.

What is the role of the hypothalamus in fever?

The hypothalamus acts as the body's thermostat. During a fever, the immune system releases pyrogens that signal the hypothalamus to raise the body's temperature set point.