chapter 18 Cutaneous Adverse Food Reactions........................
DEFINITION/OVERVIEW
Cutaneous adverse food reactions are pruritic, nonseasonal reactions associated with
ingestion of one or more substances.
ETIOLOGY/PATHOPHYSIOLOGY
Cutaneous adverse food reactions (CAFR) most appropriate term used; it is not easy
to distinguish between immunologic and nonimmunologic reactions.
Pathogenesis not completely understood: immunologic versus nonimmunologic.
Immunologic (hypersensitivity):
Reactions to glycoproteins (allergen size range of 10–70 kD)
Immediate and delayed reactions to specific ingredients
Immediate reactions presumed to be type I hypersensitivity reactions
Delayed reactions due to type III or IV reactions
Sensitization may occur at the gastrointestinal mucosa, after the offending sub-
stance is absorbed, or both.
Nonimmunologic:
Abnormal physiologic response
Food intolerance, idiosyncratic reaction; involves metabolic, toxic, or pharma-
cologic effects of offending ingredients
May be result of ingestion of foods with high levels of histamine or substancesthat induce histamine either directly or through histamine-releasing factors
May be induced by enzyme deficiencies, toxins, food additives, and contami-nants.
Antigens are normally broken down by the effects of gastric acid enzymes, pancreatic
and intestinal enzymes in the gut lumen, and intestinal cell lysosomal activity.
A natural state of tolerance is maintained by a number of immune functions: clonal
deletion, anergy, and regulatory T (Treg) cells.
Alterations in epithelial cells, antigen-presenting cells, intercellular permeability, or
any interference in the normal immune defense are likely mechanisms by which an
allergic response develops instead of tolerance.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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