Concurrent systemic lupus erythematosus and salmonellosis.

Salmonellosis was diagnosed in 4 patients with systemic lupus erythematosus (SLE). Three patients were taking prednisolone, and 3 had evidence of nephritis. All patients were febrile with clinical evidence of lupus activity at the time of diagnosis. Two patients had evidence of hyposplenism during the infection. Because salmonellosis manifests clinical symptoms like those of active SLE, the diagnosis of the salmonella infection was delayed. In 3 patients, the salmonella infection localized to a site of clinical SLE involvement and in all 4 patients, it occurred simultaneously with other bacterial infections. Multiple factors, including impaired mononuclear phagocytic system function, may predispose SLE patients to bacterial infections, especially intracellular parasites such as salmonella.