Hypereosinophilic syndrome and other rheumatic diseases with hypereosinophilia

Among the eosinophilic diseases treated by rheumatologists other than eosinophilic granulomatosis with polyangiitis, there are further organ-related and systemic diseases with hypereosinophilia. Only the exact differential diagnostic demarcation of the diseases enables a pathogenetic oriented treatment. This article focuses on the hypereosinophilic syndromes. The potential differential diagnoses of Ig(immunoglobulin)G4-related disease, eosinophilic fasciitis and drug-induced vasculitis as well as eosinophilia-myalgia syndrome and toxic oil syndrome as historic drug-induced inflammatory rheumatic diseases are described and the clinical manifestations and treatment are summarized.