August 22, 1990


Author Affiliations

New Mexico Health and Environment Department Santa Fe

New Mexico Health and Environment Department Santa Fe

JAMA. 1990;264(8):970. doi:10.1001/jama.1990.03450080055018

To the Editor.—  Clauw et al1 speculate that the pathogenesis of eosinophilia-myalgia syndrome may be related to abnormalities in tryptophan metabolism. Current epidemiologic evidence does not support this hypothesis.Our study,2 the first to provide evidence of a causal association between tryptophan-containing products and eosinophilia-myalgia syndrome, ascertained all high eosinophil counts at nine laboratories from May 1, 1989, to October 31, 1989, and found no cases of eosinophilia-myalgia syndrome with onset before July 1989. Of 429 cases reported to the Centers for Disease Control (CDC), Atlanta, Ga, by January 9, 1990, 87% reported symptom onset after July 1989.3 As of March 23, 1990, one thousand four hundred seventeen eosinophilia-myalgia syndrome cases have been reported in the United States, with 20 deaths. Seventy-six cases have been reported from other countries (CDC, Update Briefing, March 23, 1990). Since manufactured tryptophan has been consumed worldwide for years, problems with tryptophan metabolism