CLCS Unit Lesson 2A


Shellfish allergies are more often for life, so if a child is diagnosed early, they will spend the rest of their life avoiding contact. Since the offending antigen in this case is a protein common to both shellfish and fish, often the allergy for one species will be treated with the advice of avoiding all seafood in general, just to be safe (and depending upon the extent of the allergic reaction). Sometimes, the individual is sensitive enough that they can’t share the frying oil for their French fries, if other shellfish (shrimp are most common) have also been cooked in it. The potential for “cross-contamination” in this particular allergy is substantial, and makes diagnostics particularly complicated without a direct skin reactivity test.

Crustaceans (shrimp, lobster, crabs) are one category of shellfish, while mollusks (clams, mussels, oysters) make up a different set. Sometimes allergies may be relegated to one group, more commonly, they are mixed. The protein causing the allergy in shellfish is tropomyosin, which is also found in the insect order. In contrast, the common fish allergen parvalbumin is not found in shellfish, but often there may be a genetic link between the two allergies (in other words, if one allergy is present, there is a higher probability that the other will be also).

Since less expensive shellfish are often used as “filler” in artificial crab, lobster, and other combined processed foods, the labeling procedures for these packaged foods have become more stringent in order to protect those susceptible. Many pharmaceuticals will also list whether or not they contain shellfish ingredients as binding agents. People who suffer from this allergy must be dedicated to learning in what & where these ingredients may occur, and suspicious when eating out. Dependent upon the severity of the response, and the extent of cross-species sensitivity, folks with this allergy may simply avoid eating out, or any unlabeled foods, as an act of self-preservation. The recent revision of FDA Food Allergy Labeling and Consumer Protection Act (FALCPA) in 2006 is intended to simplify labeling.


Check out the following links, and add at least one new reference located either from the links contained within or in some other way to add to the resource section.

Wiki Seafood Allergy

allergic child shellfish

seafood allergies

food allergy labeling

Discussion Questions: A new child is born into a family whose parents & previous siblings have a variety of food allergies, including two who are allergic to shellfish. What dietary guidelines would you recommend for the youngest child? Is it possible to "train" the immune system through early exposure such that allergies would not develop?

Post one discussion entry under the discussion tab above responding to these questions, and reply to two other students entries.

CLCS Lesson Units Introduction

CLCS Unit Lesson 1 Vocabulary

CLCS Unit Lesson 2 Space for Discussion Task

CLCS Unit Lesson 3 Resource sharing

CLCS Unit Lesson 4 Metacognitive strategies

CLCS Unit Lesson 5 Assessment Tools

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ETAP 623 Spring 2009 Learning Commmunity