Much more common than direct infection of joints is a condition in which arthritis is associated with an immunological reaction to infection. There are two different types, which are summarized. Rheumatic fever and Henoch-Schonlein purpura follow streptococcal infections and predisposition to these disorders is not related to the presence of the antigen HLA-B27. By contrast, HLA-B27-positive individuals are particularly likely to develop reactive arthritis following enteric or venereal infection.
This poststreptococcal condition is associated with a migratory polyarthritis. A joint such as the wrist or elbow becomes acutely painful and swollen for about 2 days. As resolution occurs, another joint becomes involved. The arthritis lasts for a few weeks or months but eventually resolves completely without any long-term problems. Its importance is the association of carditis in 40% of cases.
This childhood condition also follows a streptococcal infection. It presents as a generalized purpuric rash associated with abdominal pain or a symmetrical polyarthritis, and lasts for a few weeks. Its importance is the association of glomerulonephritis in 40% of cases.