Can anemia cause fever? The indirect link explained

September 22, 2025 •

4 min read

While anemia itself does not typically trigger a fever, certain severe forms of the condition or its underlying cause may. A fever associated with anemia can signal a more complex health issue at play, prompting the question: can anemia cause fever and, if so, under what circumstances?

Quick Summary

Anemia is not a direct cause of fever, but an elevated temperature can arise from the root cause of the anemia, such as infections, inflammatory conditions, or hematologic malignancies. It is a crucial warning sign that should not be ignored, indicating a need for prompt medical evaluation.

Key Points

Indirect Cause: Anemia does not directly cause fever, but the underlying condition causing the anemia, such as an infection or inflammation, can lead to an elevated body temperature.
Hemolytic Anemia: In this type of anemia, the rapid destruction of red blood cells can trigger a systemic inflammatory response, which may present with a fever.
Aplastic Anemia: Patients with aplastic anemia have low white blood cell counts, which makes them vulnerable to serious infections that are accompanied by fever.
Important Warning Sign: A fever in anemic individuals, especially if prolonged or accompanied by other severe symptoms, is a key indicator of a potentially life-threatening infection or underlying disease.
Systemic Diseases: Conditions like autoimmune disorders, certain malignancies (e.g., lymphoma), and severe infections (e.g., sepsis, malaria) can cause both anemia and fever simultaneously.
Prompt Medical Evaluation: Anyone with both anemia and a fever should seek medical attention to determine and treat the root cause, which may be more serious than simple anemia.
Megaloblastic Anemia: Rarely, megaloblastic anemia from vitamin deficiency can be associated with fever, possibly due to the ineffective production of blood cells, and this can resolve with appropriate vitamin therapy.

Understanding the Connection Between Anemia and Fever

Fever is the body’s natural response to fight off an infection or other internal stressor. Anemia, a condition marked by a deficiency of red blood cells or hemoglobin, does not inherently cause a fever. However, when a fever occurs alongside anemia, it is a significant symptom that points toward an underlying health problem. This could be an infection, inflammation, or another serious disorder affecting the bone marrow or blood cells.

How Anemia and Fever Can Occur Together

The simultaneous presence of anemia and fever is not a coincidence but often two symptoms of a single underlying pathology. The causes are diverse and can range from acute infections to chronic diseases. Some of the most common reasons include:

Infections: Numerous infections can lead to both anemia and fever. Some pathogens can cause red blood cell destruction (hemolysis), while others suppress bone marrow function. For example, viral infections like cytomegalovirus or Epstein-Barr virus and parasitic infections like malaria can cause hemolytic anemia and fever. Sepsis, a severe systemic infection, can also lead to anemia and high fever.
Inflammatory Diseases: Chronic inflammation from autoimmune disorders like systemic lupus erythematosus (SLE) or rheumatoid arthritis can cause anemia of chronic disease. These same conditions can also cause persistent or intermittent fevers due to systemic inflammation.
Malignancies: Cancers, especially hematologic malignancies like lymphoma and leukemia, are known to cause both anemia and fever. The fever is often part of a paraneoplastic syndrome, where substances released by the cancer trigger a fever.
Specific Types of Anemia: Certain, less common forms of anemia are directly linked to fever as part of their symptom profile, as explained in the next section.

Specific Anemias Associated with Fever

Hemolytic Anemia

In hemolytic anemia, red blood cells are destroyed faster than they can be produced. When red blood cells are broken down prematurely, the process can release cellular components that trigger a systemic inflammatory response, leading to fever and chills. The destruction can be caused by infections, autoimmune attacks, or genetic disorders like sickle cell disease. For individuals with sickle cell anemia, a common and serious complication is acute chest syndrome (ACS), which presents with fever and is life-threatening.

Aplastic Anemia

Aplastic anemia is a serious condition where the bone marrow stops producing enough new blood cells, including red blood cells, white blood cells, and platelets. The lack of white blood cells (leukopenia or neutropenia) makes the individual highly susceptible to infections, which can easily cause a fever. For someone with aplastic anemia, a fever is a critical sign of a potential life-threatening infection and requires immediate medical attention.

Megaloblastic Anemia

While less common, some studies have shown a link between megaloblastic anemia (caused by Vitamin B12 or folate deficiency) and fever. It is hypothesized that the ineffective production and premature destruction of red blood cell precursors in the bone marrow could release substances acting as pyrogens (fever-causing agents). In some cases, treating the underlying vitamin deficiency can resolve the fever.

A Comparative Look at Anemia and Fever


Feature	Common Anemias (e.g., Iron Deficiency)	Anemias with Fever (e.g., Hemolytic)
Direct Cause of Fever	No. A fever is not a typical symptom of simple iron deficiency anemia.	No, but the underlying cause or mechanism of the specific anemia can be the direct cause.
Mechanism	Caused by insufficient iron, impacting hemoglobin production.	Caused by rapid red blood cell destruction, marrow failure, or systemic infection.
Associated Symptoms	Fatigue, weakness, pale skin, cold hands/feet, shortness of breath.	Fever, chills, jaundice, dark urine, enlarged spleen, frequent infections.
Severity	Often manageable with supplements and dietary changes.	Can be more severe and indicate a life-threatening underlying disease.
Treatment Focus	Replenishing iron stores and addressing diet.	Treating the root cause (infection, autoimmune disease), potentially transfusions.

When to Seek Medical Attention

If you have been diagnosed with anemia or suspect you have it and develop a fever, it is important to contact a healthcare professional. A fever combined with other symptoms can be a sign of a serious medical issue. Symptoms that, when combined with a fever, should prompt immediate medical evaluation include:

Sudden Onset of Symptoms: A rapid escalation of symptoms, especially a high fever that appears without a clear cause.
Shortness of Breath and Chest Pain: These could indicate a severe infection, acute chest syndrome in sickle cell anemia, or a cardiovascular event exacerbated by anemia.
Unexplained Bruising or Bleeding: Easy bruising, nosebleeds, or bleeding gums could indicate a low platelet count, a potential feature of aplastic anemia or another bone marrow disorder.
Persistent or Unexplained Fever: If a fever lasts for an extended period or has an unknown origin (Fever of Unknown Origin or FUO), it requires thorough investigation, especially in the presence of anemia.

Further evaluation typically involves blood tests, which will show more than just low hemoglobin. For example, a low white blood cell count (leukopenia) with a fever strongly suggests an underlying infection that requires urgent treatment.

Conclusion: The Critical Role of Underlying Causes

While the simple answer to can anemia cause fever is no, the relationship is far more complex and critically important. Fever is not a symptom of low red blood cell count alone but rather a signpost for the underlying disease process that is causing the anemia. This distinction is vital for proper diagnosis and treatment. In particular, conditions like hemolytic anemia, aplastic anemia, or severe infections can present with both anemia and fever, making it essential to look for the bigger picture. Therefore, anyone experiencing both symptoms should consult a healthcare professional to identify and address the root cause, as it could be an urgent medical matter. An informed approach can lead to timely diagnosis and effective management, preventing potentially severe complications.

For more information on the various types of anemia, symptoms, and potential complications, consult a reputable medical source such as the Mayo Clinic's Aplastic Anemia overview.

Frequently Asked Questions

The most common reason is an underlying infection. People with certain types of anemia, like aplastic anemia which affects white blood cell production, are more susceptible to infections that can cause fever.

Simple iron deficiency anemia is not known to cause a fever. If a fever is present, it is more likely due to an unrelated infection or another coexisting condition rather than the low iron levels.

Infections can range from viral (like Epstein-Barr), parasitic (like malaria), or bacterial (causing sepsis). Some infections directly destroy red blood cells, while others affect bone marrow function, leading to both anemia and fever.

Yes, you should be evaluated by a healthcare professional. A fever combined with anemia, especially a high or persistent one, is a significant symptom that requires investigation to rule out serious underlying causes like severe infection, autoimmune disease, or malignancy.

Hemolytic anemia is a condition where red blood cells are destroyed prematurely. This rapid destruction can release substances that cause inflammation and trigger a fever as part of the body's reaction to the cellular breakdown.

Yes, a fever in a person with sickle cell anemia, especially if over 101.3°F (38.5°C), should be treated as a medical emergency. It can signal a severe infection or complications like acute chest syndrome, which is life-threatening.

While rare, megaloblastic anemia caused by severe vitamin B12 or folate deficiency has been anecdotally associated with low-grade fever. It is believed to be related to the ineffective production of blood cells in the bone marrow.