Understanding Felty's Syndrome: Causes, Symptoms, and Treatment Options

Medically reviewed by Jerome Albert Ecker | MD, Assistant Professor of Medicine, Duke University - Durham, NC on August 27th, 2023.

Key Takeaways

This rare complication affects fewer than 3% of rheumatoid arthritis patients, typically developing after 10+ years of disease, with women being 3 times more likely to develop it than men.
The hallmark triad includes splenomegaly (enlarged spleen), neutropenia (white blood cell count below 2,000/μL), and active RA, leading to severe infection risk from compromised immunity.
Patients experience recurrent bacterial infections, particularly skin and respiratory tract infections, along with fatigue, anemia, and characteristic left upper abdominal pain from spleen enlargement.
First-line treatment involves disease-modifying antirheumatic drugs (DMARDs) like methotrexate, while severe cases may require rituximab infusions or granulocyte colony-stimulating factor injections.
Splenectomy becomes necessary when neutrophil counts remain dangerously low despite medical therapy, though this increases long-term infection risk and requires lifelong antibiotic prophylaxis.

Felty's Syndrome (FS) is a rare disorder that affects some people with rheumatoid arthritis (RA). It is characterized by an enlarged spleen and a very low white blood cell count. While less than 3% of people with RA develop FS, those in their 50s, 60s, and 70s who have had RA for 10 years or longer are at a higher risk. Women are three times more likely to develop FS than men, and children rarely get this condition.

Causes of Felty's Syndrome

The exact cause of Felty's Syndrome is not known, but several theories exist:

White blood cells may have stopped fighting infections effectively
Bone marrow could be producing abnormal white blood cells
The immune system may mistakenly attack white blood cells

While FS doesn't always run in families, some genes that increase the risk of developing the condition could be inherited.

Symptoms of Felty's Syndrome

The signs and symptoms of Felty's Syndrome are similar to those of rheumatoid arthritis and can overlap with other autoimmune diseases like lupus, making it difficult to diagnose. Common symptoms include:

Anemia (low red blood cell count)
Burning eyes or eye discharge
Fatigue
Fever
Loss of appetite or weight loss
Pale skin
Recurrent or persistent infections, especially in the lungs, urinary tract, or blood
Sores or brown spots on the legs
Stiff, swollen, or painful joints, usually in the hands, feet, or arms

In addition to these symptoms, people with FS have an enlarged spleen, which may cause pain behind the left rib cage or a feeling of fullness after eating.

Understanding Felty's Syndrome: Causes, Symptoms, and Treatment Options

Diagnosing Felty's Syndrome

To diagnose Felty's Syndrome, your doctor will perform a physical examination to check for an enlarged spleen. Imaging tests like an MRI or CT scan may be used to confirm the diagnosis. Blood tests will also be conducted to check for low levels of white blood cells called neutrophils, which are crucial for fighting bacterial infections.

Treatment Options for Felty's Syndrome

If your rheumatoid arthritis is well-controlled, you may not require treatment for Felty's Syndrome. However, if you do need help managing your symptoms, several options are available:

Disease-modifying drugs

Low-dose methotrexate is often used to prevent FS from progressing. Other drugs like glucocorticoids or disease-modifying antirheumatic drugs (DMARDs) used to treat RA, such as abatacept and leflunomide, may also be prescribed.

Immune system-targeting drugs

Rituximab is a preferred treatment for FS that can suppress the malfunctioning part of the immune system. These drugs are administered intravenously and may take a few weeks to show effects.

White blood cell-stimulating drugs

Granulocyte colony-stimulating factor (G-CSF) can help increase white blood cell counts and combat infections.

Home care and surgery

Your doctor will advise you on the appropriate level of physical activity and rest. Mild pain and discomfort may be alleviated with a heating pad or nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen. In severe cases where other treatments are ineffective, surgery to remove the spleen may be recommended to normalize red and white blood cell levels and reduce the risk of infection.

For more information on Felty's Syndrome and its management, consult the following resources:

The Bottom Line

Early recognition and aggressive treatment of this serious RA complication can prevent life-threatening infections while preserving immune function. Maintaining excellent rheumatoid arthritis control is crucial, as stable disease may only require careful monitoring rather than additional interventions. If you're experiencing frequent infections or abdominal pain with long-standing RA, Doctronic can help evaluate your symptoms promptly.