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Allergic and eosinophilic disorders of the gastrointestinal (GI)
tract have in common an infiltrate of eosinophils into the wall
of the GI tract—sometimes located in the lamina propria
only, sometimes in the muscularis propria, sometimes in both. The
associated disorders are highly variable in severity of symptoms
and endoscopic and histologic manifestations (Table
411-1). Different parts of the GI tract may be involved separately
or together (eg, eosinophilic esophagitis is almost always a stand-alone
disorder; eosinophilic gastritis may occur on its own, or, more
commonly as a gastroenteritis; eosinophilic colitis may occur alone, or in combination with small bowel
involvement, ie, enterocolitis). Complicating this is the fact that
eosinophils are found in the GI tract in a number of other disorders,
not considered to be primarily allergic in origin. These include
disease induced by parasitic, bacterial, and viral pathogens as
well as certain systemic diseases such as vasculitis. The general
principles, diagnostic approach, and management of food allergy
is discussed in detail in Chapter 194.
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Adverse reactions to foods have now been subclassified by the
American Academy of Allergy and Immunology into three categories: food
anaphylaxis, food hypersensitivity, and food
intolerance...