Churg-Strauss syndrome in two patients receiving montelukast

Objective. Churg-Strauss syndrome (CSS) has been described in association with the treatment of asthmatic patients with leukotriene receptor antagonist. The main mechanism proposed to explain this condition is the unmasking of CSS after the leukotriene receptor antagonist has allowed corticosteroid tapering. Other hypotheses might be proposed. Methods. We describe two patients who developed CSS after starting treatment with montelukast, a new antileukotriene drug. Results. Both patients presented with CSS after 4-5 months of treatment with montelukast. Neither patient received long-term systemic steroids for asthma, but both were oil inhaled steroids. One patient had a myocardial involvement and experienced a stroke. Our two patients were treated with systemic steroids and cyclophosphamide. Conclusions. CSS does not appear to relate to steroid tapering in our patients. The other hypotheses are a coincidence or a direct adverse effect of the antileukotriene. Long-term data on these drugs are lacking and leukotriene's role in vasculitis remains to be elucidated.