What is a fish allergy?

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An allergy to finned fish is among the top 8 most common food allergies and can be severe, potentially causing anaphylaxis, a life-threatening condition. As many as 40% of people reporting a fish allergy experienced their first allergic reaction to fish as adults, according to a study. Salmon, tuna and halibut are the most common fish that people are allergic to.

Having an allergy to finned fish does not necessarily mean one is allergic to shellfish such as shrimp, crab or lobster, as there is no relationship between shellfish and fish. However, some people may have allergies to both shellfish and fish in the same way one would have an allergy to milk and peanuts.

More than half of people who are allergic to one species of fish are allergic to all fish, so allergists tend to recommend that allergic people to avoid all fish. Some restaurants may also  swap out cheaper fish for another without notifying the customer, and there can be a high risk of cross-contamination when fish is prepared, especially in seafood restaurants. Speak with your allergist to undergo food allergy tests to discover which species of fish you can safely eat and whether or not you should avoid fish altogether.

While having an allergy to fish protein (paravalbumin) is most common, some people may also be allergic to fish gelatin, made from fish skin and bones. People with a fish allergy should talk to their doctor before consuming fish oil supplements, which may contain molecules of the allergen

Contrary to popular belief, those with fish allergies do not need to avoid iodine and radiocontrast material in medical tests, as there is no relation between iodine and fish allergies.

When are fish allergies discovered?

Unlike other food allergies that impact babies and young children, fish allergies typically do not develop until later in childhood, adolescence or adulthood. According research led by Scott H. Sicherer, MD, at the Mount Sinai School of Medicine in New York, along with other studies, around 40% of fish allergies do not occur until adulthood.

How to avoid fish

Always read labels for fish ingredients before consuming. Because it is a top 8 allergen, federal laws require that labels clearly identify if a product contains fish. Also take note of β€œmay contains” statements which detail whether or not there is a risk of cross-contamination with fish during the manufacturing process.

Fish is commonly found in Worcestershire sauce, Caesar salad/dressing and is sometimes in imitation crab products in the form of surimi, a processed fish paste made from Alaskan pollock and other fish species. Asian cuisine also uses fish-based stock for many dishes. Also steer clear of fish sticks and anchovies, which do contain β€œreal” fish.

If you eat some kinds of fish, be careful to avoid eating fish that has been in contact with the types of fish you are allergic to. Be mindful of areas where seafood is being cooked, as fish proteins may become vaporized and airborne while cooking. When dining out, be sure to ask about the fryer as many restaurants cook fish in the same oil as chicken and french fries.

Fish can often be found in:

  • Chinese, African, Indonesian, Thai and Vietnamese food

  • Caesar salad and Caesar dressing

  • Worcestershire sauce

  • Bouillabaisse

  • Imitation or artificial fish or shellfish (surimi)

  • Meatloaf

  • Barbecue sauce

  • Caponata, a Sicilian eggplant relish

  • Caviar and fish roe

  • Ceviche

Foods to avoid

  • Anchovies

  • Bass

  • Catfish

  • Cod

  • Flounder

  • Grouper

  • Haddock

  • Hake

  • Halibut

  • Herring

  • Mahi Mahi

  • Perch

  • Pike

  • Pollock

  • Salmon

  • Scrod

  • Swordfish

  • Sole

  • Snapper

  • Tilapia

  • Trout

  • Tuna

  • Fish sauce (nuoc mam or nam pla)

  • Fish sticks

  • Fish oil

Non-food products that could have fish:

  • Lotions and cosmetics

  • Vitamins

  • Medicine

  • Paint

  • Insect spray

  • Waterproofing products

Discover more!

Learn how to order in a restaurant with a fish allergy

Browse fish-free recipes