Cutaneous adverse drug reactions in patients with peripheral blood eosinophilia during antituberculosis treatment

Background/Aims: Peripheral eosinophilia during tuberculosis (TB) treatment is common, but has not been fully evaluated. The aim of this study was to determine the prevalence and clinical significance of peripheral blood eosinophilia in patients undergoing anti-TB treatment. Methods: We retrospectively reviewed the clinical and laboratory data of patients who received anti-TB treatment and had peripheral blood eosinophilia (> 5% of the total white blood cell count) at the Chonnam National University Hospital between January 2010 and December 2014. Results: Of all 2,234 patients with TB who received anti-TB treatment, 397 (17.8%) had peripheral blood eosinophilia. Of the 397 with eosinophilia, we reviewed the data of 262 (66%), and cutaneous adverse drug reactions (CADRs) were observed in 161 (61.5%). Of the 161 with CADRs, itching (47.2%) and skin rash (47.8%) were common. Older age, abnormal liver function, and higher peak blood eosinophil percentage were associated with CADRs in multivariate analysis. There was a significant relationship between increased peak eosinophil counts and the degree of severity of CADRs. Conclusions: Peripheral blood eosinophilia is a relatively common occurrence during anti-TB treatment. Peripheral blood eosinophil counts were higher according to the degree of severity of CADRs.