What is a seafood allergy?
A seafood allergy is a reaction to one or more of the proteins in crustaceans, molluscs or fish. Crustaceans include crab, lobster and shrimp. Molluscs include clams, oysters and mussels. Shellfish is a term that includes both crustaceans and molluscs.
How serious is a seafood allergy?
Seafood allergy reactions are different for each child, but they usually happen soon after your child consumes seafood. A seafood allergy carries the risk of anaphylaxis, a severe and life-threatening allergic reaction.
Seafood and fish allergies
Not all children who have a seafood allergy will have a fish allergy. However, all children who have a fish allergy are considered to have a seafood allergy, as fish is a type of seafood.
Other names for seafood
Seafood can have different names in ingredient lists. Learning these names can help you catch any hidden sources of seafood.
When buying packaged foods, always check the list of ingredients in the store and again when you bring the product home. It is also a good idea to check the ingredients every time you buy the food in case the recipe has changed. You can also call the manufacturer to ask about any recipe changes.
The following table lists some names for seafood. Use it when you are grocery shopping or calling food manufacturers.
| Crustaceans | Crab, crayfish, lobster, prawns, shrimp |
| Molluscs | Clam, cockle (sea urchin), conch, mussels, octopus, oysters, scallops, snails (escargot), squid (calamari) |
| Fish | Anchovy, bass, cap, catfish, char, cod, eel, halibut, herring, mackerel, mahi-mahi, marlin, orange roughy, pickerel (walleye), pike, pollock, salmon, sardine, trout, tuna (albacore, yellow fin, bonito), snapper, white fish |
Possible sources of seafood
Seafood is used in a wide range of packaged foods. Below is a list of some of the many food products that can contain seafood.
| Coffee | Deli meats (bologna, ham) |
| Fried rice | Gelatin |
| Hot dogs | Marshmallows |
| Salad dressing (for example Caesar dressing) | Soups and sauces |
| Spring rolls | Sushi |
| Worcestershire sauce |
What do I do if my child has a seafood allergy?
Your child should see an allergist (a doctor who specializes in diagnosing and treating allergies) who can discuss the seafood allergy with you in more detail. The allergist can discuss whether your child needs to avoid all types of seafoods, or a specific group of seafood, such as crustaceans.
Your child’s doctor will also prescribe a medication called an epinephrine auto-injector, which can be used to treat allergic reactions, in case your child accidentally eats a food containing seafood.
If my child has a seafood allergy, must they avoid all types of seafood?
If your child has a specific seafood allergy, speak to an allergist before letting them try other types of seafood.
Some people may be allergic to one group of seafood, such as crustaceans, but may be able to eat other groups of seafood, such as molluscs, as long as one group has not come in contact with the other in any way. Other times, a person might be able to eat crustaceans and molluscs but still have a fish allergy.
In addition, a person might not be allergic to complete families of seafood. For example, they might be allergic to clams but not allergic to other types of molluscs.
Your child may need to avoid all seafood due to the high chance of cross-contamination (see below), as seafood products are often processed in the same facility.
Reducing the risk of cross-contamination
Cross-contamination occurs when one substance unintentionally comes in contact with another substance, for example a potential allergen. If the substances mix together, one substance taints the other substance, making it unsafe to eat.
Food allergens can contaminate other foods when, for example, the same containers, utensils or frying pans hold a range of foods.
Bulk food containers pose a high risk of cross-contamination because they are often used for different products.
Be sure to avoid using utensils or containers that may have come in contact with allergy-causing foods and ask about possible cross-contamination when eating out.
How can my child get the right mix of nutrients if they must avoid seafood?
Key nutrients in fish can include protein, omega-3 fats, vitamin A, vitamin B12, vitamin D, vitamin E, calcium, iron and zinc. Your child can still get these nutrients even if they must avoid seafood and products that contain them.
Nutrients in seafood that are also in other foods
| Nutrient | Where to find it |
|---|---|
| Protein | Milk, red meat, chicken, egg, beans, soy |
| Omega 3 | Flaxseed oil, edamame (soybeans), radish seeds, omega-3 eggs fortified with DHA |
| Vitamin A | Sweet potato, pumpkin, liver, goat cheese, carrots, squash, spinach |
| Vitamin B12 | Milk, cheese, liver, beef |
| Vitamin D | Milk, soy beverage fortified with vitamin D |
| Vitamin E | Spinach, red pepper, Swiss chard, wheat germ cereal, egg, almonds, sunflower seeds |
| Calcium | Milk, soy beverage fortified with calcium, buttermilk, cheese, yogurt, spinach, collards, beans |
| Iron | Spinach, tomato puree, edamame, lima beans, snow peas, instant oatmeal, cereal |
| Zinc | Bran cereal, wheat germ, cheese, milk, beef, pumpkin seeds, baked beans |
Can my child with a seafood allergy enjoy sushi?
Many kinds of delicious sushi rolls do not contain any seafood. If you eat out at a sushi restaurant, contact the staff ahead of time to let them know about your child’s allergy. Ask if the restaurant can provide seafood-free sushi that is not contaminated by seafood.
When to see a dietitian for a seafood allergy
If you have removed many foods from your child's diet because of a seafood allergy, it may be a good idea to speak to a registered dietitian. The dietitian can review the foods your child still eats to decide if they are getting enough nutrients. If necessary, they can also recommend alternative foods that your child can eat safely.
Will my child always have a seafood allergy?
Most children with a seafood allergy will continue to have it as they get older. An allergist can help you find out when to test your child and see whether they have outgrown their allergy.
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When to go to the emergency room
If your child is having a severe allergic reaction to seafood, call 911 or go to your nearest emergency department immediately. If your child’s doctor prescribed them an epinephrine autoinjector, administer this medication to your child right away. See Anaphylaxis: How to recognize and respond to a severe allergic reaction for more information.
Further information
Health Canada. Crustaceans and molluscs - Priority food allergens