Question: Is a high platelet count common with rheumatoid arthritis?
Platelets are often elevated in rheumatoid arthritis.
The major target organ for this disease is the joint. There, enhanced local inflammation occurs, involving blood cells including neutrophils and macrophages. These cells also stimulate the production of platelet activating factor, which in turn causes accumulation of blood platelets, allowing them to also participate in the inflammatory reaction.
Platelets are elevated not only in RA, but also in other similar inflammatory conditions. (Answer provided by the late Dr. Raymond Federman, aka Dr. Bones, who passed away on September 2, 2003. The care of his patients even in retirement was always his joy.)