The main symptoms are joint pain and swelling of one or more joints.
A physical examination shows joint inflammation. A blood test (serology) for viruses may be performed.
Sargent JS. Polyarticular arthritis. In: Harris Ed, Budd Rc, Genovese MC, Firestein GS, Sargent JS, Sledge CB, eds. Kelley's Textbook of Rheumatology. 7th ed. Philadelphia, Pa: Saunders Elsevier; 2005: chap 35.