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Prevention
By Mayo Clinic staffIf you know you're allergic to shellfish, the only sure way to avoid an allergic reaction is to avoid all shellfish or products that might contain shellfish. Even trace amounts of shellfish can cause a severe reaction in some people. Shellfish is seldom a hidden food ingredient, so it may be easier to avoid than some other allergy-causing foods.
Avoiding shellfish
- Take caution when dining out. Eating at restaurants poses the biggest danger of mistakenly eating shellfish. When you eat at restaurants, always check to make sure the same pan, oil or utensils used for shellfish are not also used to prepare other foods. This is called "cross-contamination."
- Be especially alert at seafood restaurants. Fish and shellfish are biologically distinct, so fish will not cause an allergic reaction if you have a shellfish allergy — unless you are also allergic to fish. But when eating at a seafood restaurant, there is a higher risk of cross-contamination of your food with trace amounts of shellfish.
- Read labels. Cross-contamination can occur in stores where food may be processed or displayed along with shellfish and during manufacturing. Be sure to read food labels carefully. Companies are required to clearly label any product that contains even small amounts of shellfish or other foods that often cause allergic reactions.
- Keep your distance. You may need to completely avoid environments where shellfish are prepared or processed. Some people even have a reaction after touching shellfish or inhaling steam from cooking shellfish.
- Don't take coral calcium. Coral calcium, which is obtained from ocean coral reefs, can trigger allergic reactions, such as hives, breathing problems and swelling, in people with shellfish allergies.
Some people mistakenly believe that allergy to iodine or allergy to radiocontrast dye used in some lab procedures can cause reactions in people with a shellfish allergy. Reactions to radiocontrast material or iodine are not related.
Glucosamine, a supplement used to prevent and treat arthritis, is made from crab, lobster or shrimp shells. While it does not appear to cause an allergic reaction in most people who have a shellfish allergy, more studies need to be done to determine whether it is safe for people allergic to shellfish.
If you are at risk of a serious allergic reaction, talk with your doctor about carrying emergency epinephrine (adrenaline). If you've already had a severe reaction, wear a medical alert bracelet or necklace that lets others know that you have a food allergy.
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- Sicherer SH. Food allergen avoidance. http://www.uptodate.com/home/index.html. Accessed April 22, 2009.
- Burks W. Clinical manifestations of food allergy. http://www.uptodate.com/home/index.html. Accessed April 22, 2009.
- Wood R. The natural history of childhood food allergy. http://www.uptodate.com/home/index.html. Accessed April 22, 2009.
- James JM, et al. Respiratory manifestations of food allergy. http://www.uptodate.com/home/index.html. Accessed April 22, 2009.
- Marcus EN. Marine toxins. http://www.uptodate.com/home/index.html. Accessed April 22, 2009.
- Burks W. History and physical examination in the patient with possible food allergy. http://www.uptodate.com/home/index.html. Accessed April 22, 2009.
- Burks W. Diagnostic tools for food allergy. http://www.uptodate.com/home/index.html. Accessed April 22, 2009.
- Seafood allergy. American Academy of Allergy, Asthma & Immunology. http://www.aaaai.org/patients/advocate/2006/winter/seafood.asp. Accessed April 22, 2009.
- Seafood allergy. Asthma and Allergy Foundation of America. http://www.aafa.org/display.cfm?id=9&sub=20&cont=518. Accessed April 22, 2009.
