Shellfish Allergy

This food allergy is an immune system response linked to shellfish. It happens when your immune system treats harmless shellfish proteins as if they're a danger to your body. Shellfish include crustaceans and mollusks. Some examples include shrimp, lobster and crab. Oysters, scallops and snails are shellfish, too. A person with this allergy may be allergic to one or more of them.


What happens when a person with this allergy is exposed to shellfish? Well, they can have a wide range of reactions. Their face, lips, mouth or throat may swell. They may have red spots on their skin. They may itch and break out in hives. They may have stomach pain, nausea, vomiting or diarrhea.


If the reaction is severe, they may have trouble breathing. They may go into shock and lose consciousness. We call this "anaphylaxis." It's an emergency. Get medical help as soon as possible.

Managing this allergy

To manage a shellfish allergy, avoid shellfish and all foods that contain them. Read food labels carefully. Be careful when dining out. And watch for shellfish used as an ingredient in soups and flavorings.

Other tips

If you have this allergy, you need to stay away from places where shellfish are prepared. Don't touch shellfish. Don't inhale steam used to cook shellfish. And know that if you have this allergy, you may also be allergic to iodine or dye used in medical imaging. Your doctor will let you know if these are safe for you.