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Shellfish Allergy Diet

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An estimated 2.3% of Americans, that’s nearly 7 million people, are allergic to seafood, including fish and shellfish. Shellfish are marine animals with shells. Shrimp, crab and lobster cause most shellfish allergies.

Allergy to shellfish is considered lifelong; once a person develops the allergy, it is unlikely that they will lose it.

Approximately 60% of those with shellfish allergy first experienced an allergic reaction as an adult. To avoid a reaction, strict avoidance of seafood and seafood products is essential. Always read ingredient labels to identify shellfish ingredients. In addition, avoid touching shellfish, going to the fish market, and being in an area where shellfish are being cooked (the protein in the steam may present a risk).

There are several types of shellfish, each with different allergens. Some people are allergic to only one type and can eat the other carefully. The main two types are:

Crustaceans (crabs, lobster, crawfish, shrimp, prawns)

Mollusks (squid, snails, octopus, clams, oysters, scallops)


Should carrageenan be avoided by a fish-allergic individual?

  • Carrageenan is not a shellfish. Carrageenan, or “Irish Moss” is a red marine algae. This food product is used in a wide variety of foods, particularly dairy foods, as an emulsifier, “stabilizer”, and thickener. It appears safe for most individuals with food allergies. Carrageenan is not related to shellfish and does not need to be avoided by those with food allergies.

Should iodine be avoided by shellfish-allergic individuals?

  • Allergy to iodine, allergy to radiocontrast material (used in some radiographic procedures), and allergy to fish or shellfish are not related. If you have an allergy to fish, you do not need to worry about cross reactions with radiocontrast material or iodine.

Is glucosamine safe in shellfish-allergic individuals?

  • Glucosamine is normally safe to take because it is made from shells and not the food protein that causes shellfish allergy.


  • If you have seafood allergy, avoid seafood restaurants. Even if you order a non-seafood item off of the menu, cross-contact is possible.
  • Asian restaurants often serve dishes that use fish sauce as a flavoring base. Exercise caution or avoid eating there altogether.
  • Shellfish protein can become airborne in the steam released during cooking and may be a risk. Stay away from cooking areas.
  • Many people who are allergic to shellfish are allergic to more than one kind. Talk to your doctor so that you know for sure what foods to avoid.


All FDA-regulated manufactured food products that contain a crustacean shellfish as an ingredient are required by U.S. law to list the specific crustacean shellfish on the product label.

Avoid foods that contain shellfish or any of these ingredients:

  • Crab
  • Crawfish (crayfish, crevasse)
  • Lobster (langouste, langoustine, scamp, coral, and tomalley)
  • Prawn
  • Shrimp (crevette)

Mollusks are not considered major allergens under food labeling laws and may not be fully disclosed on a product label.

Your doctor may advise you to avoid mollusks or these ingredients:

  • Abalone
  • Clams (cherrystone, littleneck, Pismo, quahog)
  • Cockle (periwinkle, sea urchin)
  • Mussels
  • Octopus
  • Oysters
  • Snails (escargot)
  • Squid (calamari)

Shellfish are sometimes found in the following:

  • Bouillabaisse
  • Cuttlefish ink
  • Fish stock
  • Seafood flavoring (e.g. cram or clam extract)
  • Surimi

Remember shellfish avoidance and maintaining auto-injectable epinephrine are the only ways to treat an allergy. Taking an antihistamine before eating a food is not going to prevent an allergic reaction. Use caution and play it smart.

Disclaimer: This information is not intended to substitute or replace the professional medical advice you receive from your child's physician. The content provided on this page is for informational purposes only, and was not designed to diagnose or treat a health problem or disease. Please consult your child's physician with any questions or concerns you may have regarding a medical condition.

Reviewed: 02/2018

(757) 668-7000