[Eosinophilia-myalgia syndrome associated with 5-OH-tryptophan. Description of a case]

The Authors report a case of eosinophilia-myalgia syndrome in a patient with a history of alcohol abuse, treated with a 5-OH-tryptophan containing drug. As regards the pathogenesis of this "new" clinical syndrome, three major hypotheses can be considered: a) autoimmune, according to which tryptophan could act as an "immunogenic" stimulus, thus evoking a cell-mediated reaction against neuromuscular structures; b) dysmetabolic, that is to say, related to neurotoxic metabolites of tryptophan, which in certain conditions could be degraded by an "alternate" pathway that is normally less operating; c) toxic, which is the most accredited nowadays, according to which there is a toxic factor, perhaps similar to aniline, linked to the process of manufacture and purification of L-tryptophan. In our patient, the drug withdrawal and a therapy with steroids led to the remission of the syndrome.