Felty’s syndrome (FS) affects fewer than 1% of people with RA – and RA occurs in about 1% of the population. The true prevalence of FS is difficult to determine since some people do not have symptoms. With the discovery of stronger and more effective anti-rheumatic medications, the number of people with FS may be decreasing.

Felty’s syndrome commonly develops in people in their 50s, 60s and 70s who have had rheumatoid arthritis for more than ten years. It most often occurs in the Caucasian population. FS is rarely found in children. It is believed that women are about three times more likely to be affected by FS than men, although since some people do not experience symptoms, and others do not report symptoms, it is difficult to say with accuracy how many women vs. men develop FS. Men develop FS earlier in the course of RA than women do.

People with FS may experience infections such as pneumonia or skin infections. They may also experience a general feeling of discomfort – or “malaise” – fatigue, loss of appetite and weight loss, pale colour, and eye burning and/or discharge. In some cases, people with FS may have ulcers on the lower legs, and discoloration or abnormal brown pigmentation of the skin, particularly on the legs. Other symptoms include low levels of circulating red blood cells (anemia), a decrease in circulating blood platelets that assist in blood clotting functions, and/or inflammation of the blood vessels (vasculitis). It is also possible that people with FS will have no symptoms, or that their symptoms will be attributed to their RA. There is no single test for FS – it is diagnosed based on the presence of RA, an enlarged spleen and a low white blood count.

The cause of FS is not known, however there are indications that a number of factors can contribute to this condition. White blood cells, produced in the bone marrow, might be developing abnormally. Or white cells may not be circulating in the bloodstream because they are being stored in the spleen. A third possibility is that the immune system is destroying white blood cells.

Treatment of FS is not always required, especially if the underlying RA is well-controlled. If people with FS experience recurring infections, active arthritis, and/or leg ulcers, they may be prescribed gold salts, methotrexate, azathioprine, penicillamine, cyclosporin and, more recently, tacrolimus. Some people require a combination of medications before the body responds. People with severe infections may benefit from weekly injections with a stimulating factor (granulocyte stimulating factor/GSF) that increases the amount of white blood cells. Surgical removal of the spleen is considered only in situations of severe, repeated infections and hospitalizations. This approach has not been evaluated by long-term research studies.

In general, people with FS should maintain their health as best as they can. It is important to get an annual flu shot and avoid crowded areas during flu outbreaks, as well as to alert friends and family to “stay away” if they have the flu or colds. Washing hands thoroughly and frequently also helps to prevent infection, as does protecting lower legs from knocks and bruising, and treating cuts and abrasions promptly according to a doctor’s advice. If you have FS, it is a good idea to wear a medical alert bracelet or neck chain at all times and to keep a record of medications, blood test results and any unusual symptoms.