Felty’s Syndrome (M05.0)

Introduction and Etiology

Felty’s syndrome is a complex medical condition that arises as a consequence of rheumatoid arthritis inflammation. Common symptoms of Felty’s syndrome include skin pigmentation spots, decreased white blood cell count in the blood, splenomegaly, and various arthritis symptoms. It is a rare condition that significantly compromises the human immune system.


Thus far, Felty’s syndrome lacks distinct and entirely specific symptoms due to its rarity and incomplete study. However, at times, entirely similar fever symptoms, severe weight loss, lymph node enlargement, muscle atrophy, subcutaneous nodules, multiple neuropathies, and multiple membrane inflammations may manifest, along with atypical disease development in humans.


  • Despite numerous clinical studies, the exact nature of Felty’s syndrome formation remains unknown. It is only recognized that 1-5% of patients with seropositive rheumatoid arthritis exhibit a progression to Felty’s syndrome.
  • Symptoms typically appear after a prolonged period of illness (approximately 10 years) in an age group over 40 years old, primarily among women. Children are rarely affected.
  • Autoimmune processes have been identified as the primary cause, involving lymphoid tissue (lymph nodes and some organs) in the process. This results in the formation of antibodies and immune complexes, disrupting the normal functions of bone marrow and white blood cells.
  • This is accompanied by a decrease in white blood cell count and severe resistance to infectious agents. Even if infections penetrate the body, they become exceedingly difficult to treat. In some cases, complete splenectomy is the only effective measure.

Clinical Picture

  • Joint involvement peculiar to rheumatoid arthritis inflammation.
  • High prevalence of systemic phenomena such as:
  • Rheumatoid nodules.
  • Sjögren’s syndrome.
  • Lymph node enlargement.
  • Multiple neuropathies.
  • Multiple membrane inflammations.
  • Skin sensitivity.
  • Ocular skin inflammation.
  • Hepatomegaly, with the possibility of developing portal hypertension (rarely).
  • Reactive infections.


  • Splenic rupture.
  • Reactive infections.
  • Portal hypertension with bleeding in the digestive system.

Laboratory Data

  • Increased erythrocyte sedimentation rate.
  • Decreased white blood cell count less than 1.5 × 10^9 / liter.
  • Decreased platelet count.
  • Presence of rheumatoid factor at high concentrations.
  • Presence of antibodies recognizing cellular protonic aspects.
  • Detection of antibodies against neutrophil cytoplasm.
  • Slight elevation in alkaline phosphatase and transaminase levels, which should be considered in the detailed diagnosis of liver and spleen syndrome.

Instrumental Data

  • Bone marrow examination (extraction): may show normal bone marrow, a normal number of large blood plates, and enlargement in myeloid tissues with maturation disorder.

Diagnostic Approach:

Felty’s syndrome typically develops against the background of destructive rheumatoid arthritis over a long period, accompanied by systemic manifestations. Therefore, diagnosing Felty’s syndrome involves decoding the white blood cell deficiency in patients with rheumatoid arthritis. Cytopenias in rheumatoid arthritis may result from the medications used. Bone marrow extraction assists in resolving this issue.


General Approach:

There is no conclusive evidence in medical literature favoring one medication over another in treating Felty’s syndrome. However, most experts prefer core medications such as methotrexate and gold compounds. Corticosteroids are secondary-line medications. Bone marrow stimulants are used to treat white blood cell deficiency.

Pharmacological Treatment:

  • Primary treatment not only helps reduce clinical symptoms of arthritis but also increases blood cell count:
  • Gold salts.
  • Methotrexate at a dose of 7.5-15 mg/week.
  • Penicillamine.
  • Corticosteroids: Effective in high doses, but tapering to lower doses (<10 mg) may lead to relapse. Prolonged use of high corticosteroid doses is not typical in rheumatoid arthritis and increases the risk of reactive infections with Felty’s syndrome.
  • Bone marrow stimulant usage is beneficial in the presence of reactive infections and white blood cell deficiency. It is administered at a dose of 5 mg/kg/day, and if there is no effect after 2-3 weeks, the dose is doubled. Treatment is discontinued when the peripheral blood neutrophil count exceeds 1.0 × 10^9/L and is maintained at this level for three consecutive days. However, there are reported cases of worsening rheumatoid arthritis with bone marrow stimulant usage.
  • Surgical Treatment: In rare cases when conservative treatment is ineffective, splenectomy is performed. It should be noted that 25% of patients with white blood cell deficiency experience recurrence after splenectomy. Splenectomy does not reduce the recurrence of reactive infections in Felty’s syndrome patients.


  • Felty’s syndrome can lead to the development of Hodgkin lymphoma.
  • White blood cell deficiency less than 1.0 × 10^9/L accompanies severe reactive infection development.


Article Author:

Dr. Ibrahim Mansour
A general practitioner and orthopedic specialist with 9 years of experience in the emergency department. Specializes in treating infectious diseases and gastrointestinal diseases, with a focus on skeletal aspects using therapeutic, surgical, and conservative methods for injuries, including sports-related ones, and major joint diseases in the extremities. His area of interest includes joint-preserving procedures in the knee and hip joints.