Development of Churg‑Strauss syndrome with severe multiple mononeuropathy after leukotriene receptor antagonist treatment in one of the monozygotic twins with asthma

Several cases of Churg‑Strauss syndrome (CSS) have been reported in asthmatic patients treated with leukotriene receptor antagonists (LTRAs). It is not clear whether LTRA is a causative factor in the development of vasculitis. We present the case of a 26‑year‑old patient, who developed severe central and peripheral neuropathy after a short‑term treatment with LTRA, followed by gastrointestinal perforation and bleeding. The patient was successfully treated with high‑dose glucocorticoids, immunoglobulins, and cyclophosphamide. His monozygotic twin brother treated for asthma does not meet classification criteria for Churg‑Strauss syndrome at the moment, but his condition is being monitored. Both asthma and rheumatology specialists should consider the possibility of CSS development in patients treated with LTRAs.