Diagnosis: Churg-Strauss syndrome
Churg-Strauss syndrome (CSS)—also known as allergic granulomatosis and angiitis—is a rare multisystemic vasculitis of small- to medium-sized vessels characterized by asthma, chronic rhinosinusitis, and prominent peripheral blood eosinophilia.1,2 Mean diagnosis age is 50 years with no gender predilection.2 Any organ system can be affected, although the lungs are most commonly involved, followed by the skin.1,2
Based on criteria from the American College of Rheumatology, the diagnosis of CSS can be made if 4 of the following 6 criteria are met: (1) asthma, (2) eosinophilia >10% on a differential white blood cell (WBC) count, (3) paranasal sinus abnormalities, (4) a transient pulmonary infiltrate detected on chest x-ray, (5) mono- or polyneuropathy, and (6) a biopsy specimen showing extravascular accumulation of eosinophils.2
Skin biopsy specimen from our patient showed leukocytoclastic vasculitis with prominent tissue eosinophilia. Laboratory studies showed an elevated WBC count of 12,300/mcL (reference range, 4500-11,000/mcL), and eosinophilia of 40% (reference range, 1%-4%). A serologic test for perinuclear pattern antineutrophil cytoplasmic antibodies (p-ANCA) was positive. (More on this in a moment.) Radiography of the chest showed transient pulmonary infiltrates.
Based on the clinical and laboratory findings, the patient was positive for 4 of 6 criteria and given a diagnosis of CSS.