What are some causes of polyarthritis?

Causes of polyarthritis that persists for more than six weeks include systemic lupus erythematosus, osteoarthritis, rheumatoid arthritis, ankylosing spondylitis and fibromyalgia, according to the American Academy of Family Physicians. Human parvovirus B19 infection sometimes causes pain in multiple joints that lasts for less than six weeks.

Doctors typically maintain flexibility when diagnosing patients who present with polyarticular pain, or pain in more than four joints, because of the variety of diagnoses that can result, explains the American Academy of Family Physicians. Diagnostic tools such as urinalysis, blood tests and Xrays assist physicians in making accurate determinations. In some cases, physicians may need to examine patients several times over a span of weeks to reach definitive diagnoses.