chapter 23 Eosinophilic Disease (Granuloma) Complex...................
DEFINITION/OVERVIEW
Cats: Feline eosinophilic dermatitis or eosinophilic granuloma complex (EGC) is
often a confusing term for four distinct syndromes grouped primarily according to
their clinical similarities as a disease complex, their frequent concurrent (and recur-
rent) development, and their positive response to antiinflammatory therapeutics.
EGC is a description, not a diagnosis:
Eosinophilic plaque
Eosinophilic granuloma
Indolent ulcer
Allergic miliary dermatitis.Dogs: canine eosinophilic granuloma (CEG) uncommon; not part of a disease com-
plex; specific differences from cats are listed within the text.
ETIOLOGY/PATHOPHYSIOLOGY
Eosinophilic plaque: hypersensitivity reaction, most often to insects (fleas,
mosquitoes), food or environmental allergens; exacerbated by mechanical trauma.
Eosinophilic granuloma: multiple causes; idiopathic, genetic predisposition, and
hypersensitivity.
Indolent ulcer: may have both hypersensitivity and genetic causes.
Allergic miliary dermatitis: not always included within the EGC; very common hyper-
sensitivity reaction, most often to fleas.
Eosinophil: major infiltrative cell for eosinophilic granuloma, eosinophilic plaque,
and allergic miliary dermatitis, but not indolent ulcer; most often associated with
allergic or parasitic conditions, as well as a more general role in the inflammatory
reaction.Several reports of related affected individuals and a study of disease development in
a colony of specific pathogen-free cats indicate that genetic predisposition may be a
significant component for development of eosinophilic granuloma and indolent ulcer.A heritable dysfunction of eosinophil regulation has been proposed.
CEG (dogs): may have both a genetic predisposition and a hypersensitivity cause;
insect bite often incriminated.
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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