Shellfish

Shrimp, lobster, squid, crabs, and oysters are examples of shellfish, which are fish having an exterior made of hard or shell-like material. Allergies in shellfish are typically brought on by tropomyosin, a kind of protein present in shellfish. Hives, skin rashes, and itching are a few minor signs that someone is sensitive to shellfish.

Wheezing, low blood pressure, and even anaphylaxis, which can be deadly, can also occur in more severe cases. All shellfish can cause negative responses in some persons with a shellfish allergy, but only specific kinds may need to be avoided.