Overview

When you have a shellfish allergy and you eat shellfish, your body reacts as if the shellfish are trying to cause harm. It fights back by setting off an allergic reaction. A mild reaction may include a few raised, red, itchy patches of skin (called hives). A severe reaction may cause hives all over, swelling in the throat, trouble breathing, or fainting. It can also cause belly pain, nausea, vomiting, or diarrhea. This is called anaphylaxis (say "ANN-uh-fuh-LAK-suss"). It can be deadly.

A good way to prevent an allergic reaction is to avoid the foods that cause it. Shellfish might be used as ingredients in surimi (imitation shellfish, which is often found in sushi) and fish sauce. An allergy doctor or a dietitian may be able to help you understand which foods might be okay and what to avoid. Learn what to do if you have a reaction.

How can you care for yourself at home?

During a mild reaction

• Take a non-drowsy antihistamine, such as loratadine (Claritin), as your doctor recommends. Be safe with medicines. Read and follow all instructions on the label.

During a severe reaction

• Give yourself an epinephrine shot. Keep it with you at all times. Make sure it has not expired.
• Call for emergency help. A severe allergic reaction can be life-threatening and is a medical emergency.

To prevent future reactions

• Avoid the foods that cause problems. And try not to use utensils or cookware that may have been in contact with food that you are allergic to.
• Teach your family members, co-workers, and friends what to do if you have a severe reaction to a food that you are allergic to.
• Wear medical alert jewellery that lists your allergies.