Fish: includes salmon, tuna, cod.
Crustaceans: includes shrimp, lobster, crab.
Mollusks: snails, bivalves (mussels, scallops, oysters), squid.

Cross-Reactions

Within a seafood group …

Dr. Scott Sicherer, author of Understanding and Managing Your Child’s Food Allergies and associate professor of medicine at the Mount Sinai School of Medicine’s Jaffe Food Allergy Institute, concludes from his 2006 review of seafood allergy studies:

- That 30 to 50 per cent of those with an allergy to one of the seafood groups will react to more than one type of fish or shellfish.

However, you can also be allergic to just one type of fish or shellfish. It’s even possible to be allergic to just one type of shrimp.

- That it is common for people to be allergic to more than one shellfish. Sicherer finds up to 80 per cent who are allergic to one crustacean may be sensitized to others, and “40 per cent may react upon ingestion.”

In one study reviewed, blood samples from nine patients with shrimp anaphylaxis reacted to the proteins of 13 crustaceans and mollusks. As well, he finds between 10 and 15 per cent allergic not only to other crustaceans, but to mollusks as well.

- That the risk of reacting to more than one fish is high. Sicherer suggests to speaking to your allergist: “Your allergist may take into consideration the severity of your allergy, test results, and dietary preferences to determine what it is you can and can not eat.”

- That about 50 per cent with a mollusk allergy react to more than one mollusk.

Between shellfish and fish …

According to Sicherer, only about 10 per cent react to both, which have quite different key allergenic proteins (tropomyosin in shellfish; parvalbumin in fish).

Remember, however, that there may be cross-contact between the two groups at grocery seafood counters or in restaurants.

Sources: UpToDate 2006; interview Dr. Scott Sicherer

Does your child refuse to eat a certain food, or complain that it makes his “tongue hurt”? These could be signs of a food allergy, and should be taken seriously.

It is common for the symptoms of food allergy to vary by individual – and from reaction to reaction in the same person. Not everyone will get all the symptoms, which range greatly in severity from mild to severe (and even fatal): your throat may feel tight on one exposure to your allergen or you may get itchy hives on your skin and vomiting with the next.

The Range of Symptoms

-Tingling in the mouth
-Swelling of the tongue and throat / feeling of throat tightness
-Itchy skin, hives or skin redness
-Abdominal cramps
-Vomiting or diarrhea
-Breathing difficulty, wheezing
-Faintness due to a sudden drop in blood pressure

Anaphylaxis

Anaphylaxis is the severe form of allergic reaction. It involves one or more of the body’s symptoms; for example, the gastrointestinal tract, the respiratory tract, the skin and the cardiovascular system. A person experiencing anaphylaxis often has difficulty breathing, and the person could lose consciousness. Anaphylaxis puts a person at risk of death.

Anaphylactic reactions can come on quickly, and it’s impossible to know when a reaction will become severe. It’s important that people with food allergies are prepared for a reaction by always carrying an epinephrine auto-injector (either EpiPen or Twinject).

Experts recommend using epinephrine early if a person known to be at risk of anaphylaxis begins to show signs of allergy symptoms – don’t wait until the symptoms worsen, as it may become to difficult put a halt to the reaction once it’s in progress.

Symptoms reviewed by Dr. Susan Waserman

Label Aware – Fish and Shellfish Allergy

Reading labels is a way of life when you have fish or shellfish allergies. Before eating anything in a package, be sure to read the label carefully. Look for hidden sources of fish or shellfish and other names for fish or shellfish.

Also be on the lookout for precautionary statements. These are statements that indicate an allergen may be in the food, due to cross contamination during processing. Examples of precautionary statements include: “May contain fish” and “Manufactured in a facility that also processes shrimp and crab.”

Allergists generally advise people with fish or shellfish allergies to avoid all products that include precautionary statements about their allergen.

If you are ever uncertain about whether a food product is safe for you, call the manufacturer to confirm. When in doubt, don’t eat it.

In Canada, new regulations (2012) require food manufacturers list priority allergens in plain language on packaging, rather than using rarely known specific names – ie. tarama or orange roughy (fish) or quahaugs (shellfish). The ingredients within listed ingredients that are priority allergens would also have to be shown. For example, manufacturers couldn’t simply list “gelatin” if the source of the gelatin is a priority allergen, such as fish.

More on Canada’s 2012 Food Allergen Regulations.

In the United States, the Food Allergen Labeling and Consumer Protection Act went into effect in 2006. FALCPA requires manufacturers to use plain language when listing the top 8 priority allergens, and to declare all allergens either in the ingredient list, or in a “Contains:” statement at the end of the list.

The allergens included in this regulation are milk, eggs, fish, shellfish, tree nuts, wheat peanuts and soybeans. The Canadian regulations also add sesame and mustard as priority allergens, while separate legislation requires companies to declare sulfites if they are present at more than 10 parts per million, or if they had a technical or functional effect in the food.

Both the United States and Canada are studying ways to regulate the precautionary statements used on packaged food labels.