Churg-Strauss Syndrome: Clinical Symptoms, Complementary Investigations, Prognosis and Outcome, and Treatment

Churg-Strauss syndrome (CSS), first described in 1951, is a rare vasculitis of small-and medium-sized vessels. It is characterized by a constant association with asthma and eosinophilia, and by the presence of anti-myeloperoxidase (MPO) anti-neutrophil cytoplasmic antibodies (ANCA) in similar to 40% of the patients. Vasculitis typically develops in a previously asthmatic and eosinophilic middle-aged patient and most frequently involves the peripheral nerves and skin. Other organs, however, may be affected and must be screened for vasculitis, especially those associated with a poorer prognosis, such as the heart, kidney, and gastrointestinal tract, as assessed by the recently revised Five-Factor Score (FFS). Overall survival of CSS patients is excellent, but relapses are not uncommon and require maintenance or steroid-sparing therapies, depending on the original FFS-based prognosis at diagnosis. All patients require corticosteroids, often for prolonged periods, combined with immunosuppressants [eg, induction (cyclophosphamide) and maintenance therapy (azathioprine)], for those with poorer prognoses. Recent insights, especially concerning clinical differences associated with ANCA status, showed that CSS patients might constitute a heterogeneous group, both clinically and pathogenically. Future therapies might reflect these differences more strongly.