Small Animal Dermatology, 3rd edition

chapter 48 Vasculitis...........................................

DEFINITION/OVERVIEW

 Specifically denotes the targeted damage of blood vessels by inflammation; often

inferred from tissue changes consistent with a disruption in blood flow.

 Inflammation may be neutrophilic (leukocytoclastic or nonleukocytoclastic), lym-

phocytic, eosinophilic, granulomatous, or of mixed cell type.

 Leukocytoclastic vasculitis is the inflammation of small blood vessels seen as perivas-

cular nuclear fragments; may be a major feature seen histologically.

 Clinical signs related to type or size, location, and cause of vessel(s) affected.

 May be associated with additional or underlying conditions, a drug reaction, or

idiopathic.

 Cutaneous adverse reaction to food associated with urticarial vasculitis.

 Pathomechanisms: type III (immune complex) and type I (immediate) reactions:
Endothelial damage caused by infectious agent, parasite infestation, endotoxin,

or immune complex deposition along the vessel wall

Initiation of local inflammation, neutrophil accumulation, and complement

activation

Neutrophils release lysosomal enzymes leading to necrosis of vessel wall, fibri-

noid change, endothelial swelling, thrombosis, and hemorrhage

Polyarteritis nodosa: systemic vasculitis with intimal (vascular smooth muscle

cell) proliferation and vessel wall degeneration and necrosis; leads to microa-

neurysm, hemorrhage, thrombosis, and necrosis of involved vessels and adjacent

tissues.

 Nondermal vasculitis (e.g., renal, hepatic, and serosal surfaces of body cavities) may

be the mechanism leading to development of clinically apparent signs of systemic

disease (e.g., polyarthritis and proteinuria) without causing obvious external lesions.

SIGNALMENT/HISTORY

 Any age, breed, or sex may be affected.

 Predisposed breeds: dachshund, rottweiler, Chinese shar-pei, greyhound, German

shepherd, Scottish terrier, Jack Russell terrier, St Bernard.

Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dermatology, Third Edition.
Karen Helton Rhodes and Alexander H. Werner.
©2018 John Wiley & Sons, Inc. Published 2018 by John Wiley & Sons, Inc.

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