Shellfish Allergies and What You Need to Know About Them

Shellfish Allergies

You could be allergic to shellfish and not even be aware that you have this allergy. If you are not a big fan of seafood or shellfish then you may have never tried eating these foods. If you have never eaten the food before, then how would you know if you are allergic?

Are You Allergic to Shellfish?

The simple answer is that you wouldn’t know you had an allergy to shellfish. But sometimes what you don’t know can kill you. If you are ever at a doctor’s office and they say you need more tests including a CAT Scan (CT Scan) or an MRI there are a few things you may want to do before you have the tests. Please be sure to tell them if you have a shellfish or iodine allergy, or have previously had a reaction to the testing dye.

A nurse or technician should ask you if you are allergic to shellfish before they administer the dye or contrast solution for the scan. Not to induce fear of these tests but during these scans, a percentage of patients have had reactions to the dye and consequently find out they are allergic to shellfish. While you are enclosed inside a big medical device is not the time you want to start having an allergic reaction. If you have other seasonal allergies or indoor allergies you might want to go ahead and get an allergy test for shellfish, just to be on the safe side.

Types of Shellfish: Lobster, Shrimp, Clams, Scallops, Prawns, Mussels, Crab, Abalone, Crayfish, and Periwinkles (a type of snail).

Reactions Include Hives, Itching, Swelling, Rash, Redness, Coughing, Headache, Tingling, Wheezing, Nausea, Dizziness, Difficulty Breathing, Loss of Balance, Muscle Paralysis, Anaphylaxis Shock, Rapid Heartbeat and more.

If you have had a reaction mild or severe after eating any of the listed types of shellfish you may be allergic. You might want to go to an allergy doctor and get a skin test to see if you truly are allergic and find out how to control your allergy. It is also good to be mindful that many recipes and food dishes that you might not be aware of may contain shellfish.

What to Avoid?

Food and recipes you may want to avoid because of your shellfish allergy are some soups, seafood buffet tables, sushi, frying oil and shellfish cross-contamination. Some people with seafood allergies must stay completely away from certain types of restaurants altogether.

It’s a good thing to note that you can become allergic to shellfish at any time. You may have eaten lobster or shrimp and never had a problem before. Then the very next time you eat a clam your throat begins to swell and you have breathing problems. It is also possible for symptoms of this allergy to worsen over time. There are many shrimp lovers out there who will not stop eating their favorite shrimp just because they have a small reaction to the shellfish. If you know you have an allergy to shellfish you should carry an over the counter allergy medication with you, in-case you can’t stop yourself from eating your favorite food.

Some over the counter allergy medicines that can help with reactions are Zyrtec, Benadryl, Claritin, and Alavert. You may also need to carry an EpiPen with you, check with your doctor to find out more.


  • Jackson T. Margrave “Shellfish.” Hodgepodge Hut.
  • Mayo Clinic Staff “Shellfish Allergy.” Mayo Clinic.