Final answer:
Anaphylaxis and anaphylactoid reactions are both severe allergic reactions, but they differ in their underlying mechanisms.
Step-by-step explanation:
Anaphylaxis and anaphylactoid reactions are both types of severe allergic reactions, but they have some important differences. Anaphylaxis is a systemic and potentially life-threatening type I hypersensitivity reaction. It is triggered by an allergen and involves a massive release of histamines, resulting in symptoms such as a drop in blood pressure, changes in heart rate, shortness of breath, and swelling of the tongue and throat. Anaphylactoid reactions, on the other hand, are similar to anaphylaxis in terms of symptoms, but they are not mediated by immunoglobulin E (IgE) antibodies like anaphylaxis is.