This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Microbiology
Hypersensitivity vasculitis is seen most commonly in 
Select and explain. 
A. Postcapillary venules, B. Aerioles, C. Veins, D. Capillaries
A: Postcapillary venules
Answer: A: Postcapillary venules 
Explanation: HYPERSENSITIVITY VASCULITISIn hypersensitivity vasculitis, postcapillary venules are the most commonly involved vessels, capillaries and aerioles are involved less frequently.It is primarily a disease of small vessels.It is characterized by leukocytosis, a term that refers to the nuclear debris remaining from the neutrophils that have infiltrated in and around the vessels during the acute stages.