Managing Shellfish and Fish Allergies

in Fish & Shellfish
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There is no cure for allergies to fish or shellfish, so people who develop allergies to seafood must avoid even small traces of the foods that cause them to react.

It’s crucial that people with an allergy to seafood carry epinephrine with them at all times. (As well as other medications their allergists may recommend, such as asthma inhalers and antihistamines).

It’s also important to remember that epinephrine is considered an emergency measure – not a treatment – so people should avoid taking unnecessary risks. But with a few simple precautions, people with allergies to seafood should be able to lead full, normal lives.

What’s Safe?

It’s possible to be allergic to just one or two forms of fish or shellfish – for example, some people can eat lobster but not scallops, while others can eat cod but not salmon. However, there commonly a high level of cross-reactivity within the food groups, so many people need to avoid either fish or shellfish in all their forms. Work with your allergist to understand your own seafood allergy or allergies.

It is important to note, however, that the key allergens in fish and shellfish are completely unrelated, so even if you are allergic to shellfish, finned fish might be just fine. (There are people who are allergic to both fish and shellfish, but this is not common.) Again, do discuss your condition with your allergist.

Accepting Allergies to Seafood

Many people with seafood allergies develop them later in life, which can be tricky, because they may be accustomed to eating without restrictions. “But I’ve never had a problem with seafood,” is a common refrain, so sometimes people take unnecessary risks and try to eat the food that has caused them to react. But once you have a seafood allergy, it’s very important to avoid the allergen altogether. Although you might have a relatively mild reaction (e.g. hives or swelling) on one occasion, a severe or even life-threatening reaction can occur on subsequent exposure.

Know What You’re Eating

Seafood comes in many different forms. Shellfish can include mollusks, with a two-part shell, such as clams, mussels, and oysters. Shellfish also refers to crustaceans such as shrimp, prawns, lobster, crabs and crayfish. Other forms include squid (the main ingredient in calamari), octopus, periwinkle, limpets, abalone, cockles, quahogs, snails (or “escargot”), langoustines and sea urchins. The most common shellfish allergy is to shrimp.

There are many different types of fish, including anchovies, bass, bluefish, catfish, char, chub, cod, eel, flounder, grouper, haddock, hake, halibut, herring, mackerel, mahi-mahi, marlin, monkfish, perch, pickerel, pike, pollock, rockfish, salmon, sardines, shark, smelt, snapper, sole, sturgeon, swordfish, trout, tuna, turbot, whitefish and more.

It is very important that you understand the different names of the food you are allergic to, and carefully read all food labels so you can avoid them.

One thing to be cautious of with seafood allergies: imported foods. Not all countries have the stringent labeling requirements of the United States, Canada and the European Union. Don’t take chances if you suspect fish or shellfish could be ingredients of an import.

Hidden Sources of Seafood 

While by law fish and shellfish must be labeled on packaged foods, it is important to read those labels, since seafood can turn up in unexpected places. Examples include: some brands of Worcestershire sauce, salad dressings, sauces, sushi, scampi, gumbo, jambalaya, bouillabaisse, spring rolls, chowder and some types of pizza. Asian foods commonly have fish and shellfish in their ingredients, so make sure to be extra careful when reading labels, and be mindful that cross-contact can occur in processing.

Be aware that most “imitation seafood” actually contains seafood – for example, imitation crab often contains crab – so don’t assume the product is safe, and carefully read all ingredients.

Some of the most common hidden sources of seafood are not in human food. These include plant fertilizers, fish food, lip balm, skin exfoliating products, and in pet foods. If you’re not sure of the ingredients, contact the manufacturer.

Because many types of shellfish are rich in iodine, some shellfish-allergic people believe that they must avoid iodine – a common ingredient in everything from table salt to X-ray dyes. This is incorrect: the allergen in shellfish is in the flesh of the food, and not in the iodine, so iodine should be safe to consume. (Some people cannot tolerate iodine, but this is a separate issue.)

Carrageenan is made from a marine algae, not fish or shellfish, and so is considered safe for people with fish and shellfish allergies.

Watch Out for Supplements

One of the main hidden sources of seafood is omega-3 supplements, which are often made from ingredients such as cod liver oil and other fish oils. Many of these products are safe for seafood-allergic people to consume, because the oils are so highly refined that they have no allergic proteins left in them.

Another supplement called glucosamine, which is often used to treat arthritis, is made from the shells of crustaceans. Recent studies have shown that because the shells contain no shellfish proteins, the supplement are usually considered safe for people with shellfish allergies. However, there have been reports of reactions to glucosamine in shellfish-allergic people, so you may want to stick with the vegetarian forms of glucosamine, which contain no seafood at all.

Just make sure to check with your allergist, and with the manufacturer of the product, before trying any supplements.

Dining Out and Allergies to Seafood

Seafood can be especially difficult to avoid in a restaurant setting. For those with fish or shellfish allergies, most seafood restaurants should be avoided altogether. Chinese, Japanese, Vietnamese, Korean and Thai restaurants can be especially heavy on fish and shellfish, so it’s important to look at the menu and speak to someone at the restaurant before choosing to eat there.

Some people with severe allergies to fish or shellfish may even react to proteins in the air from cooking seafood. So being in a seafood restaurant, especially if you are seated in close proximity to the source of cooking or steaming, can lead to symptoms.

Once you find a restaurant that isn’t seafood-heavy, call ahead and ask the manager or chef about menu items and how they handle pans and the grill to avoid cross-contact. If you don’t get solid answers, or the establishment can’t accommodate you, move on to a different restaurant.

When you arrive at the restaurant, tell your server about your allergy and discuss menu items that will be safe. If you don’t feel he or she is able to answer your questions properly, ask to speak to the chef or the manager. If you’re still unsure, head for the door, or stick with a beverage.

Seafood Cross-Contact

It’s important to make sure the food you’re allergic to doesn’t come in contact with the food you are eating. Cross-contact is a particular problem in restaurants, where pans and utensils may be shared. Make sure your server and the kitchen staff understand that even trace amounts of seafood may be a problem for you.

At a pub serving many deep-fried foods, ask if the deep fryer is shellfish-free. (Often it isn’t.) For example, if you have a shrimp allergy, don’t order those deep-fried zucchini sticks if they’re cooked in the same deep fryer oil as the popcorn shrimp.

Call the Manufacturer

If you’re unsure about whether a particular product contains seafood, contact the manufacturer by email or phone. Most companies are accustomed to getting product inquiries from the public and are happy to help. If they can’t give you clear answers, try a different product instead.

School and Fish or Shellfish Allergies

Although more common in adults, children can have seafood allergy as well. For a parent of a child with seafood allergies, it’s important to communicate clearly with your child’s teacher and the principal, and to create an anaphylaxis emergency care plan (also called a food allergy action plan) to protect your child.

Look into federal 504 Plans as well as local school board policy and your state (or provincial in Canada) food allergy laws where they exist. Such a plan should ensure that, in addition to the school nurse, the main teacher is trained on the food allergy symptoms, and the allergy emergency protocols.

Be sure your allergic child knows not to share food with peers and not to take food from anyone, including the teacher, unless you’ve said it’s OK.

An Adult Plan for Allergies to Seafood

Adults too require an emergency plan with seafood allergies. Have your epinephrine auto-injectors and other medication on hand, and make sure that your loved ones know how to administer the auto-injector. And don’t forget to wear a medical ID bracelet or necklace.

Make it your rule – no epinephrine auto-injector means no food; and if your child is allergic, make sure this rule is one he or she takes seriously.

Inform your close friends, loved ones and colleagues about your allergy, and don’t be shy about asking for what you need in order to be safe. Sometimes people don’t fully understand food allergies – and they may have a lot of questions. But before long, they’ll get the picture.
Live Well!

Don’t let your seafood allergies take over your life. With the necessary precaution, vigilance and a little extra planning, the vast majority of allergic people can live full, normal, healthy lives.

– Article last updated September, 2020.