Final answer:
Anaphylaxis is a severe and potentially life-threatening type I hypersensitivity reaction. It is characterized by a drop in blood pressure and bronchial smooth muscle contractions. Epinephrine is commonly used to treat anaphylaxis.
Step-by-step explanation:
Anaphylaxis is a severe and potentially life-threatening type I hypersensitivity reaction. It can be caused by various allergens such as shellfish, peanuts, and latex. Anaphylaxis is characterized by a drop in blood pressure, bronchial smooth muscle contractions, and systemic mast cell degranulation. Epinephrine is commonly used to treat anaphylaxis as it helps raise blood pressure and relax bronchial smooth muscles.