hello
First step should be a consultation with a rheumatologist
some serum,blood tests ad x ray of joints for confirmation of nature of
arthritis and diagnosis
if rheumatoid is confirmed on tests then, evaluation of liver and kidney functions tests for for pre-evaluation before starting specific group of medicines for rheumatoid arthritis
Avoidance of foods depends on known allergy to any food stuff subjectively and any history of development of rashes, hives after particular fooditem eaten
You may go for serum
rheumatoid factor,anti-ccp, ESR,ASO titre,ANA,
complete blood count initially for proceeding further on this
ESR comes down after disease process is controlled by medicines- for rheumatoid-they are
methotrexate,hydroxychloroquin,leflunamide,
prednisone etc whic can be selected fromafter establishing diagnosis and liver,kidney status