Final answer:
Shellfish and iodine allergies can increase the risk of anaphylaxis, a severe allergic reaction that can be life-threatening due to symptoms like throat swelling and a drop in blood pressure.
Step-by-step explanation:
Shellfish and iodine allergies are linked to an increased risk of anaphylaxis, a severe and potentially life-threatening allergic reaction. Allergies are caused by a hypersensitivity of the immune system to substances that are usually harmless, such as certain foods. When the immune system overreacts to an allergen like shellfish, it can cause a range of symptoms, from watery, itchy eyes, and sneezing to more severe conditions like hives, eczema, and anaphylaxis. Anaphylaxis involves symptoms such as swelling of the tongue and throat, blocking of airways, a dangerous drop in blood pressure, and potential shock, which can lead to death if not treated promptly.