Which of the following is most commonly involved in Hypersensitivity vasculitis:
Answer is C (Post-capillary venules): Post-capillary venules are most commonly involved in Hypersensitivity vasculitis Hypersensitivity vasculitis Hypersensitivity vasculitis refers to small vessel vasculitis that is restricted to the skin and not associated with any other form of primary or secondary vasculitis. Implicit in the definition is that this condition is not associated with medium or large vessel disease at other sites, nor with small vessel disease in other organs (only skin) Microscopic polyangitis affects the skin and also internal organs and hence is not considered pa of hypersensitivity vasculitis The typical histopathological feature of cutaneous vasculitis is the presence of leukocytoclastic vasculitis of small vessels. Vasculitis is charachterized by Leukocytoclasis -- Harrison's Synonyms for Hypersensitivity vasculitis include: cutaneous small vessels vasculitis, leucocytoclastic vasculitis, cutaneous leucocytoclastic angitis etc. 'Post-capillary venules are the most commonly involved vessels. Capillaries and aerioles may be involved less frequently' -- Harrison American College of Rheumatology 1990 Criteria for the Classification of Hypersensitivity Vasculitis Laboratory and Radiographic Work-up of Patients with Possible Hypersensitivity Vasculitis Age at disease onset > 16 years Medication at disease onset Palpable purpura Maculopapular rash Biopsy including aeriole and venule, showing granulocytes in a perivascular or extravascular location For purposes of classification, hypersensitivity vasculitis may be diagnosed if the patient meets at least three of these five criteria.
Capillaries
Aerioles
Post-capillary venules
Medium sized aeries