Allergies to shellfish are among the most common allergies that adults suffer from. If you have a family history of food allergies, your chance of developing a shellfish allergy is much greater than if neither of your parents is allergic to any foods. Your allergic reaction to shellfish is the result of your immune system misidentifying shellfish proteins as dangerous substances. When you consume a shellfish allergen, your body releases antibodies, which in turn release chemicals that cause a variety of allergic symptoms.
Most commonly, people with allergic reactions to shellfish suffer symptoms on their skin, such as hives, itching, swelling, eczema and rashes. Other common symptoms of a shellfish allergy are wheezing, nausea, vomiting, diarrhea and dizziness. A more serious shellfish allergy symptom is anaphylaxis, which can result in death. Its symptoms are constricted airways, a significant drop in blood pressure, a fast pulse, dizziness and even loss of consciousness.