Low incidence of reactive arthritis in children following a salmonella outbreak

Objectives-To assess the incidence of reactive arthritis (ReA) in an outbreak of salmonella infection in a large cohort of children in Germany. Methods-A few days after the salmonella outbreak all parents of affected children and all paediatricians and general practitioners in the region were provided with detailed information about the possibility of ReA. Six weeks after the outbreak a telephone call was made to all general practitioners and paediatricians to identify patients with ReA. Ten weeks after the outbreak a questionnaire assessing symptoms of ReA was mailed to all parents, and after a period of 4 months paediatricians; and general practitioners were contacted again to search for additional unreported cases of ReA. Results-Of the 286 children (age range 11 months to 9 years) with diarrhoea and stool cultures positive for Salmonella enteritidis lysotype 8/7, not a single case of arthritis was reported over the 4 month period. However, six children (2%) had arthralgia of various duration (1 day to 6 weeks) with a single recurrence in one child. The joint pattern was oligoarticular and lower limb joints (knee/ankle) were affected exclusively. Conclusion-The incidence of ReA after salmonella infection in children appears to be very low which may be related to differences in the immune response between children and adults.