Eosinophilic neuritis, perimyositis, and vasculitis associated with ingestion of L-tryptophan.

Four cases are described of a clinical syndrome which developed in the setting of L-tryptophan ingestion. The major manifestations consisted of myalgias, neuropathy, weakness, and profound eosinophilia. Pathologically a vasculitis involving predominantly small veins was observed along with a mixed cellular infiltrate in the perimysium and epineurium. Clusters of eosinophils were characteristically noted in the tissue specimens. The clinical course appears to be chronic although further longterm followup will be required. One patient pursued a relentless downhill course with progressive neurologic impairment and death. Although the mechanism of tissue injury in these individuals is speculative, the possible association of this widely used nonprescription medication with this syndrome should be recognized.