Churg-Strauss syndrome and leukotriene antagonist use: a respiratory perspective

BACKGROUND: Churg-Strauss syndrome (CSS) is a rare granulomatous small vessel vasculitis that occurs against a background of longstanding asthma. Leukotriene antagonists (LTAs) are used in the management of asthma and may facilitate a reduction in steroid dosage. Reports of the development of CSS in patients with asthma following the initiation of LTA therapy suggest either a causal association or an unmasking of latent CSS as steroid doses fall. We have undertaken a systematic review to establish whether evidence of a drug induced syndrome exists. METHODS: Systematic review searching Medline from database inception to August 2007 to identify cases with a possible association between LTAs and CSS. Hill's criteria of causation were used to assess strength of causality. RESULTS: 62 cases in which CSS developed after the introduction of LTA therapy were identified. Patients were divided into three groups: group 1 had received no previous steroid therapy; group 2 had been treated with oral and/or inhaled corticosteroids, but had no change in steroid therapy following LTA introduction; and group 3 had a clear reduction in steroid therapy following introduction of LTA therapy. The majority of patients from each group exhibited a clear temporal relationship between initiation of LTA and development of CSS, with no evidence of pre-existing disease. CONCLUSIONS: Currently available evidence suggests an association between LTA and CSS that may be causal.