Final answer:
In severe allergic reactions, systemic mast cell degranulation can lead to anaphylactic shock, treated with epinephrine. Carrying an epinephrine injector can be lifesaving for those with severe allergies.
Step-by-step explanation:
When a person with allergies comes into contact with an allergen like shellfish, peanuts, or bee venom, their immune system can overreact, even though these allergens are innocuous to most people. In severe cases, this can lead to anaphylactic shock, a rapid allergic reaction that causes widespread systemic mast cell degranulation, leading to a dangerous drop in blood pressure and the constriction of airways due to bronchial muscle contractions. To treat this, epinephrine is often administered, which raises the blood pressure and relaxes the bronchial muscles, potentially saving the patient's life. Those with known severe allergies are advised to carry automatic epinephrine injectors, which can provide immediate treatment during an anaphylactic episode, especially in situations far from medical facilities.