Eosinophilia-myalgia syndrome in Germany: an epidemiologic review

To review the epidemiologic features of eosinophilia-myalgia syndrome (EMS) in Germany.

We determined the incidence of EMS in Germany through May 1992 and analyzed the dose of L-tryptophan used, the duration of intake, and the concurrent medications.

All patients receiving L-tryptophan preparations in Germany were already under medical supervision before the onset of the disease; thus, information on patient history and other potential risk factors was readily available. Because of the drug status of L-tryptophan preparations, brands could be accurately traced back to suppliers of raw materials. Statistical differences in age and gender of patients, dose of L-tryptophan, eosinophil count, and skin involvement were sought between patients with and those without concurrent medications.

On the basis of guidelines established by the Centers for Disease Control and Prevention, 105 patients fulfilled the criteria for EMS. No apparent correlation was found between the incidence of EMS and the dose of L-tryptophan or the duration of intake before onset of EMS. Assessment of the study group showed that 45% were taking various other medications, whereas 55% were taking L-tryptophan only. Analysis by type of pharmaceutical agent showed no preponderance of a specific concurrent drug (in particular, psychotropic drugs). Thus, concurrently used medications did not seem to be an important variable. All cases of EMS were associated with L-tryptophan from formulators that had used raw materials from the previously implicated source.

This study supports the pathophysiologic role of a contaminant in L-tryptophan in the occurrence of cases of EMS in Germany.