We describe 13 adult patients with reactive arthritis induced by tonsillitis. Arthritis occurred 710 days after tonsillitis and involved the wrists, knees, feet and sternoclavicular joints. Some cases had pain in the Achilles tendon areas. Synovial fluid examined in 4 patients was sterile. All patients except 3 showed unequivocal elevation of serum ASO and/or ASK. Streptococcus was isolated from tonsillar swabs in 7 patients.
One had maculopapular erythema and 2 had abdominal pain of unknown origin, but none had cardiac involvement, chorea and subcutaneous nodule. HLA examination revealed that 4 had B39 (p <0.005). Eight cases were treated with antibiotics. Five cases underwent tonsillectomy. All tonsils had cryptic abscess. No exacerbation was seen thereafter. These cases probably represent reactive arthritis induced by tonsillitis and should be distinguished from other rheumatic diseases.