[498] Immunoglobulin-A Associated Small Vessel Vasculitis: A Ten-Year Experience at the Massachusetts General Hospital.

Katy Linskey, Daniela Kroshinsky, Mai Hoang. Massachusetts General Hospital, Boston

Background: Leukocytoclastic vasculitis (LCV) together with vascular IgA deposition on direct immunofluorescence (DIF) are not pathognomonic of Henoch-Schonlein purpura (HSP), as a previous community-based series has shown that infection was often the cause of non-HSP IgA vasculitis (Am J Dermatopathol 1999;21:234-240).
Design: We performed a retrospective analysis to determine the strength of association of IgA vascular deposition with HSP. 67 patients with a histologic diagnosis of LCV and accompanying DIF studies were identified between 3/2000 and 7/2010. All cases exhibited leukocytoclasia, fibrinoid necrosis of the vessel walls, and erythrocyte extravasation. Of those, 31 cases had vascular IgA deposition on DIF examination and 27/31 had available clinical information.
Results: Using the American College of Rheumatology 1990 classification criteria for HSP, which requires at least two of four criteria (age ≤ 20, palpable purpura, abdominal pain, histologic evidence of LCV) in order to distinguish HSP from other forms of vasculitis; 23/27 (85%) met criteria for HSP. Two criteria were met in 65% (15/23), three criteria in 26% (6/23), and all four criteria in 9% (2/23). 20/23 patients (87%) had palpable purpura, 13/23 (57%) had renal manifestations, 9/23 (39%) had abdominal pain, 8/23 (35%) had arthralgias, and 2/23 (9%) were ≤ 20 years old. Out of the remaining non-HSP yet IgA+ cases (15%) where the etiology was apparent, half were due to drug hypersensitivity (2/4).
Conclusions: The presence of IgA deposition on DIF is not pathognomonic of HSP since only 85% of IgA+ small-vessel vasculitis was clinically diagnosed as HSP in this series. Our findings showed that in a hospital-based population such as ours, non-HSP IgA+ vasculitis was most commonly due to drug hypersensitivity.
Category: Dermatopathology

Monday, February 28, 2011 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 74, Monday Morning

 

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