The cause of Felty syndrome is unknown. It is more common in people who have had rheumatoid arthritis (RA) for a long time. People with this syndrome are at risk for infection because they have a low white blood cell count.
Exams and Tests
A physical exam will show:
- Swollen spleen
- Joints that show signs of RA
- Possibly swollen liver and lymph nodes
A complete blood count (CBC) with differential may show a low number of white blood cells called neutrophils. Nearly all people with Felty syndrome have a positive test for rheumatoid factor.
An abdominal ultrasound may confirm a swollen spleen.
In most cases, people who have this syndrome are not getting full treatment for RA. They may need other medicines to suppress their immune system and reduce the activity of their RA.
Methotrexate may improve the low white blood cell count.
Granulocyte-colony stimulating factor (G-CSF) may raise the neutrophil count.
Some people benefit from removal of the spleen (splenectomy).
Without treatment, infections may continue to occur.
RA is likely to get worse.
You may have infections that keep coming back.
When to Contact a Medical Professional
Call your health care provider if you develop symptoms of this disorder.
Prompt treatment of RA with currently available medicines markedly decreases the risk of developing Felty syndrome.
Seropositive rheumatoid arthritis (RA); Felty's syndrome
Aoki E. Felty's syndrome. In: Ferri FF, ed. Ferri's Clinical Advisor 2017. Philadelphia, PA: Elsevier; 2017:469.
Bellistri JP, Muscarella P. Splenectomy for hematologic disorders. In: Cameron JL, Cameron AM, eds. Current Surgical Therapy. 12th ed. Philadelphia, PA: Elsevier; 2017:603-610.
Erickson AR, Cannella AC, Mikuls TR. Clinical features of rheumatoid arthritis. In: Firestein GS, Budd RC, Gabriel SE, McInnes IB, O'Dell JR, eds. Kelley and Firestein's Textbook of Rheumatology. 10th ed. Philadelphia, PA: Elsevier; 2017:chap 70.
O'dell JR. Rheumatoid arthritis. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 264.
Review Date 4/24/2017
Updated by: Gordon A. Starkebaum, MD, Professor of Medicine, Division of Rheumatology, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.