Why is my spleen getting bigger? Understanding the Causes of Splenomegaly

September 29, 2025 •

3 min read

The human spleen, an organ normally about the size of a person's fist, can enlarge for many reasons, from infections to underlying systemic diseases. Understanding why is my spleen getting bigger? is the first step toward effective diagnosis and treatment, as splenomegaly is often a sign of another health issue.

Quick Summary

An enlarged spleen, or splenomegaly, is a common finding caused by a range of conditions, including infections, liver disease, blood disorders, and cancers. Its enlargement can result from increased workload, abnormal blood flow, or infiltration by disease, and often requires medical investigation to determine the root cause.

Key Points

Symptom, Not a Disease: An enlarged spleen, or splenomegaly, is a sign of an underlying health problem, not a disease itself.
Common Causes: Common culprits include infections (viral, bacterial, parasitic), liver diseases (cirrhosis), and blood cancers (leukemia, lymphoma).
Overworked Spleen: It often enlarges when it's overworked due to filtering out damaged blood cells or fighting a systemic infection.
Diagnosis is Key: A doctor needs to perform tests to determine the specific cause behind the enlargement.
Treatment Targets the Cause: Treatment focuses on addressing the root issue, and may include medication or, in severe cases, surgery to remove the spleen.
Watchful Waiting: In some cases, if the enlargement is minor and asymptomatic, a doctor may recommend monitoring it over time.

The Spleen: A Vital, Yet Vulnerable, Organ

Your spleen is a soft, spongy organ in the upper left abdomen that plays a critical role in your immune system, filtering blood and removing old or damaged red blood cells. When the body is challenged by infection or disease, the spleen's activity increases, which can lead to swelling.

How Your Spleen Works and What Causes It to Enlarge

The spleen acts as a blood filter and is part of the lymphatic system, containing white blood cells to fight pathogens. Its structure makes it prone to enlargement when stressed. Splenomegaly can stem from various causes, affecting its function and size.

Common Causes of an Enlarged Spleen

Splenomegaly is a symptom of another condition. Identifying the root cause is essential for treatment. Frequent causes include:

Infections

Viral Infections: Mononucleosis is common, especially in young people. Other viruses like CMV and HIV can also cause enlargement.
Bacterial Infections: Conditions like endocarditis or syphilis can lead to swelling.
Parasitic Infections: Malaria is a notable cause, particularly in certain regions.

Liver Diseases

Cirrhosis: Scarring of the liver can increase pressure in the portal vein, causing the spleen to enlarge.
Portal Hypertension: High blood pressure in the vein leading to the liver can cause blood backup into the spleen, leading to swelling.

Blood Cancers and Disorders

Leukemia: Overproduction of abnormal white blood cells can accumulate in the spleen.
Lymphoma: Cancers of the lymph tissue can affect the spleen.
Hemolytic Anemia: The spleen works harder to filter damaged red blood cells, causing it to swell.
Sickle Cell Disease: The spleen filters abnormal red blood cells, leading to congestion and enlargement.

Infiltrative and Metabolic Conditions

Gaucher Disease: An inherited disorder causing fatty substance buildup in organs like the spleen.
Amyloidosis: Buildup of abnormal protein in organs.

Inflammatory and Autoimmune Conditions

Lupus: Can cause an overactive immune response and inflammation.
Rheumatoid Arthritis: A condition causing widespread inflammation, including in the spleen.

Diagnosis and Management of an Enlarged Spleen

A doctor will work to identify and treat the underlying cause. This may involve a physical exam, blood tests, and imaging like ultrasound, CT, or MRI.

When to Seek Medical Attention

While some enlarged spleens are asymptomatic, consult a doctor if you experience:

Pain or fullness in the upper left abdomen, potentially spreading to the left shoulder
Fatigue
Frequent infections
Easy bleeding

Treatment Options

Treatment is determined by the cause. Options may include:

Antibiotics: For bacterial infections.
Cancer treatments: For blood cancers.
Medications: To manage autoimmune conditions.
Splenectomy: Surgical removal may be necessary in severe cases. Those without a spleen need extra infection precautions.

Comparison of Causes of Splenomegaly


Cause Category	Example Conditions	Mechanism of Enlargement	Typical Symptoms (in addition to splenomegaly)
Infections	Mononucleosis, Malaria	Increased immune response fighting pathogens	Fever, fatigue, sore throat
Liver Disease	Cirrhosis, Portal Hypertension	Backup of blood flow, increased pressure	Jaundice, abdominal swelling, fluid retention
Blood Cancers	Leukemia, Lymphoma	Infiltration by abnormal, cancerous cells	Unexplained weight loss, night sweats, fatigue
Blood Disorders	Hemolytic Anemia, Sickle Cell	Increased workload filtering damaged blood cells	Anemia, fatigue, paleness
Autoimmune Disease	Lupus, Rheumatoid Arthritis	Systemic inflammation and overactive immune system	Joint pain, skin rash, organ inflammation

How to Manage Your Health

Understanding potential causes is important. If you suspect an issue, seek medical advice for proper diagnosis and treatment. For more information on spleen health, consult resources like the National Institutes of Health.

Conclusion

An enlarged spleen is an indicator of an underlying issue, such as infections, liver disease, blood cancers, or autoimmune disorders. Professional diagnosis is vital for the correct treatment. Early detection and management of the cause are key to effectively handling splenomegaly and preventing complications.

Frequently Asked Questions

Splenomegaly is the medical term for an enlarged spleen. It is not a disease but rather a symptom indicating an underlying health condition, such as an infection, blood disorder, or liver disease.

An enlarged spleen can sometimes be felt by a doctor during a physical exam, but it often doesn't cause noticeable symptoms until it is significantly enlarged. Some people might experience pain or a feeling of fullness in the upper left abdomen.

Viral infections, particularly mononucleosis, are among the most common causes of a temporarily enlarged spleen. However, other frequent causes include liver disease and certain blood cancers.

Yes, if the underlying cause is treated and resolved, the spleen can often return to its normal size. For example, a spleen enlarged by mononucleosis will typically shrink once the infection has passed.

You should see a doctor if you experience any pain or fullness in your upper left abdomen. If you have severe pain, especially radiating to the left shoulder, seek immediate medical attention as it could signal a ruptured spleen.

Spleen removal (splenectomy) is considered a last resort for severe or chronic cases. The body can function without a spleen, but you will have an increased risk of serious infections and will need vaccinations to compensate for the lost immune function.

There is no specific diet to treat an enlarged spleen directly. However, maintaining a healthy diet and lifestyle, especially if the underlying cause is liver disease related to alcohol, can be beneficial for overall health.