Microscopic examination of the biopsy specimen revealed a dermal perivascular and interstitial infiltrate with neutrophils, red blood cells, and numerous eosinophils as well as obliterated blood vessel walls with nuclear dust and neutrophils, consistent with a leukocytoclastic vasculitis.

Additional laboratory studies demonstrated an elevated white blood cell count of 17Ìý000/µL (reference range [RR], 4500-11Ìý000/µL) and eosinophilia of 32% (RR, 1%-3%). The IgE level was elevated at 1828 IU/mL (RR, 0-160 IU/mL). Serologic tests were negative for perinuclear and cytoplasmic pattern antineutrophil cytoplasmic antibodies. Radiography and computed tomography of the chest showed transient pulmonary infiltrates. The findings of bronchoscopy and transbronchial biopsy were unremarkable.