Eosinophilic fasciitis associated with L-tryptophan ingestion

A 62 year old woman taking L-tryptophan developed eosinophilic fasciitis shortly after starting an exercise class. She received prednisone without benefit but improved after azathioprine treatment was started and L-tryptophan was discontinued. As products containing L-tryptophan have recently been implicated in development of the eosinophilia-myalgia syndrome it is suggested that the use of L-tryptophan might have contributed to the development of eosinophilic fasciitis in this patient. Similarities with toxic oil syndrome are noted. Additional studies are warranted to determine the prevalence of L-tryptophan ingestion among patients diagnosed as having eosinophilic fasciitis.