IgE-mediated allergic reactions

• Systemic anaphylaxis

  • route of entry: intravenous, either directly or following rapid absorption

  • however, “we do not give peanuts IV.” what this slide means is that if you eat enough peanuts, the antigen will get from your GI tract into your bloodstream, and this counts as intravenous entry

  • response: edema, increased vascular permeability everywhere, tracheal occlusion due to increased SM contraction and edema, circulatory collapse, and death

• Acute urticaria (wheal-and-flare)

  • the wheal is the light part in the center of the lesion; it is caused by increased interstitial pressure due to excessive edema

  • around it a red flare of blood

  • the appearance is caused by local increase in blood flow and vascular permeability

  • allergens can be insect bites, allergy testing

• Allergic rhinitis

  • antigens are inhaled lightly/sniffed

• Asthma

  • antigens are inhaled deeply

• Food allergy

  • peanuts should be on the top of the list

  • shellfish

  • most people think they are “allergic” to milk. figure out if they have lactose intolerance or a real allergy

  • gluten—suspect this when you see a fussy kid whose parents are shorter than the rest of their siblings

Category: Pathology Notes