[A case of Churg-Strauss syndrome with elevated IgG4--the association between treatment and IgG4].

We report the case of a 57-year-old woman, known to have had allergic sinusitis and bronchial asthma, and had been treated with leukotriene receptor antagonist for one month, at the time of presentation. She complained of bilateral weakness and pain in her lower extremities and her laboratory investigations revealed an elevated absolute eosinophil count of 23,357/μl, elevated biliary enzymes and an IgG4 level of 594 mg/dl. Nerve conduction study revealed mononeuritis multiplex. She was therefore diagnosed with Churg-Strauss syndrome and started on pulse steroids and intravenous immunoglobulins. Her symptoms were alleviated, her absolute eosinophil count and biliary enzymes both improved at the same time and her IgG4 level also decreased. Although elevated biliary enzymes occurring with CSS was thought to be due to a bile duct eosinophilic granuloma, we cannot rule out the possibility of IgG4-related sclerosing cholangitis, because of her elevated IgG4.