Which syndrome is the rare small vessel necrotizing vasculitis associated with asthma, allergic rhinitis, lung infiltrates, eosinophilia, and extravascular necrotizing granulomas?

• A. Granulomatosis with polyangiitis
• B. Microscopic polyangiitis
• C. Churg-Strauss Syndrome
• D. Polyarteritis nodosa

Answer: (C)

The main concept is recognizing eosinophilic granulomatosis with polyangiitis, also known as Churg-Strauss syndrome. This is a rare small-vessel necrotizing vasculitis that classically occurs in people with asthma and allergic rhinitis and is marked by peripheral eosinophilia. The lung involvement often shows infiltrates, and tissue shows extravascular necrotizing granulomas with eosinophil-rich inflammation. This combination—asthma plus eosinophilia with granulomatous, necrotizing small-vessel vasculitis—is distinctive for EGPA.

Granulomatosis with polyangiitis tends to present with upper airway and renal involvement and does not characteristically feature asthma or marked eosinophilia. Microscopic polyangiitis lacks granulomatous inflammation and eosinophilia. Polyarteritis nodosa involves medium-sized arteries, often spares the lungs, and lacks the eosinophil-rich granulomatous pattern seen in EGPA. Therefore, the described syndrome fits eosinophilic granulomatosis with polyangiitis (Churg-Strauss).