Eosinophilia-myalgia syndrome: a long-term follow-up study

In this case-series analysis, of 34 patients originally identified with eosinophilia-myalgia syndrome (EMS), 31 survivors were followed-up by yearly telephone interviews. We ascertained type, duration, and severity of symptoms and whether certain patient characteristics were associated with illness improvement. At a median of 3.6 years after onset, 3 patients (8.8%) had died. Two (5.9%) were well, 7 (20.6%) were improved, and 22 (64.7%) reported either no change or worsening overall condition compared to 1 year prior. Musculoskeletal and neurologic symptoms predominated. The prevalence of several symptoms, including muscle cramps, joint pain, and cognitive symptoms, increased over the course of study. Age, sex, peak eosinophil count, early prednisone use, and usual dose or duration of L-tryptophan use were not associated with significant improvement. We conclude that for the majority of patients, EMS is a chronic illness having a major impact on life-style 3.6 years after onset. The chronic, often worsening pattern of illness suggests an ongoing pathogenetic mechanism.