A shellfish allergy causes an allergic reaction when you eat shellfish. Sometimes, a shellfish allergy is only to certain kinds of shellfish, or you may have an allergy to all shellfish. Shellfish include marine animals with shells, such as shrimp, crab, and lobster, as well as octopus and squid.

Shellfish allergy can cause mild symptoms, such as hives or nasal congestion, or more-severe and even life-threatening symptoms. For some people, even a tiny amount of shellfish can cause a serious reaction.

If you think you have a shellfish allergy, talk to your doctor. Tests can help confirm a shellfish allergy, so you can take steps to avoid future reactions.

Jun. 23, 2011