Eosinophilia in rheumatologic diseases: a prospective study of 1000 cases

The role of eosinophilia in connective tissue diseases and the relationship between symptoms of rheumatic disease and eosinophilia have not been clearly established. The purpose of the present study was to explore the prevalence of eosinophilia in rheumatologic disease and determine its relationship to the symptoms. One thousand patients who applied to our rheumatology outpatient clinic between 2001 and 2002 were prospectively studied. The upper limit of normal blood eosinophil numbers was determined as 500 cells/microl of blood. A detailed history was obtained from all patients and careful physical examination was done. A negative correlation was observed between eosinophilia and dryness of the mouth, vitiligo, and fatigue (P < 0.05). Nonsteroidal anti-inflammatory drug usage correlated positively with eosinophilia, which was also statistically meaningful (P < 0.05). Twenty-six of our patients with fibromyalgia (n = 293), three of our subjects with rheumatoid arthritis who were using methotrexate (n = 182), 15 of whom who were not on methotrexate therapy, and one of the 26 with vasculitis had eosinophilia, which was not statistically significant (P > 0.05). None of the patients with scleroderma (n = 12) had eosinophilia. Eleven of the patients with gout had eosinophilia, and only one of them was using allopurinol. We conclude that eosinophilia can be seen in various rheumatologic conditions but, as corticosteroids are one of the most common medications used in collagen tissue diseases, the eosinophil numbers found may be lower than expected and eosinophilia may be more frequent than reported.