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Type I Hypersensitivities quiz

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  • What type of antibody mediates Type I hypersensitivities?
    Type I hypersensitivities are mediated by IgE antibodies.
  • How quickly do Type I hypersensitivity reactions typically occur after allergen exposure?
    They usually occur within about thirty minutes of exposure.
  • What is an allergen?
    An allergen is an exogenous antigen that originates outside the human body and triggers hypersensitivity reactions.
  • What cells are sensitized during the initial exposure to an allergen in Type I hypersensitivity?
    Mast cells and basophils are sensitized by IgE antibodies during the initial exposure.
  • What happens to mast cells and basophils upon re-exposure to the allergen?
    They degranulate, releasing pro-inflammatory mediators like histamine.
  • What is the main pro-inflammatory mediator released during Type I hypersensitivity reactions?
    Histamine is the main pro-inflammatory mediator released.
  • What is the difference between localized allergic reactions and systemic anaphylaxis?
    Localized reactions are confined to the exposure site or a single organ system, while systemic anaphylaxis affects multiple organ systems and can be life-threatening.
  • What is anaphylactic shock?
    Anaphylactic shock is dangerously low systemic blood pressure caused by widespread blood vessel dilation and leakage, leading to organ failure or suffocation.
  • Name two common allergens that can cause systemic anaphylaxis.
    Common allergens include insect venom (bee or wasp stings) and foods like peanuts and shellfish.
  • What medication is commonly used to treat systemic anaphylaxis?
    Epinephrine, often administered via an EpiPen, is used to treat systemic anaphylaxis.
  • How does epinephrine help during anaphylaxis?
    Epinephrine constricts blood vessels, prevents leakage, and helps unblock airways to reverse life-threatening effects.
  • What test is commonly used to diagnose allergies?
    The Prick Puncture Skin Test (PPST) is commonly used to diagnose allergies.
  • What indicates a positive result in the Prick Puncture Skin Test?
    A wheal and flare reaction, with a raised inflamed area and surrounding redness, indicates a positive result.
  • What is the goal of immunotherapy desensitization for allergies?
    The goal is to reduce the severity of the allergic response, often by promoting IgG antibody production.
  • How do IgG antibodies help in desensitization therapy?
    IgG antibodies bind to the allergen before IgE antibodies can, reducing the severity of the allergic response.