Montelukast-associated Churg-Strauss syndrome

A 68-year-old asthmatic presented markedly unwell with arthralgia, mononeuritis multiplex, peripheral neuropathy, and eosinophilia. His past medical history included perennial rhinitis, and nasal polyps. Three months prior to admission his prednisolone was stopped and Montelukast was started. The diagnosis of Montelukast-associated Churg-Strauss syndrome was made. The drug was stopped and steroids started with general improvement and reduction of eosinophilia; however, the neurological deficit persisted.