Fish Allergy – Everything you need to know

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If you or your child have recently been diagnosed with a fish allergy, I’m sure you’re feeling overwhelmed, confused, and lost as to where to start with research. You might be wondering what suddenly brought it on. Or maybe you’re wondering what foods are off-limits now?

If that sounds like you, then don’t worry. Below I’m sharing Everything You Need To Know About Fish Allergy. I’ll walk you through what it is, symptoms and reactions, and even tips for managing allergies at home.

raw salmon fillets over a blue surface.
Top view of raw salmon steak isolated on blue background. Minimal concept. Flat lay.

What Is A Fish Allergy?

Fish allergy is a physical reaction to finned fish. This reaction happens when a person with an allergy to fish is exposed to fish, proteins in the fish bind to specific IgE antibodies and trigger the person’s immune defenses, leading to reaction symptoms that can be mild or very severe.

According to, “Finned fish is one of the most common food allergies with a prevalence of 1% in the U.S. population. In one study, salmon, tuna, catfish, and cod were the fish to which people most commonly reported allergic reactions”

It’s also important to note that, just because you have a fish allergy, it doesn’t necessarily mean that you’re allergic to shellfish.

Fish Allergy Symptoms And Reactions

When a person is allergic to fish, their immune system overreacts to the proteins found in fish. Instead of fighting infections, the immune system releases chemicals, like histamine, that treat the proteins as a foreign invaders, which is why someone develops symptoms and reactions.  

Allergic reactions to finned fish account for a significant percentage of serious allergic reactions to food, they include:

  • Hives or skin rashes
  • Wheezing
  • Trouble breathing
  • Abdominal pain
  • Vomiting
  • Diarrhea
  • Headaches
  • Swelling
  • Drop in blood pressure
  • Anaphylaxis


Anaphylaxis is a severe and potentially life-threatening condition that can be fatal if not met with immediate care. Its symptoms include:

  • Constriction of airways
  • Pain and cramping in the abdominal region
  • Rapid loss in blood pressure
  • Shock or loss of consciousness 

If you or someone you love is experiencing any of these conditions, call 911 immediately. To know more about this severe allergic reaction, check out my post about What Is Anaphylaxis and How Is Treated.

How Is An Allergic Reaction To Fish Treated?

A mild allergic reaction may be treated by an oral over-the-counter antihistamine, but a more severe reaction may cause your doctor to prescribe an EpiPen in case of emergency.

What Causes A Fish Allergy?

There are a few causes that can trigger a fish allergy attack. It could be:

eggless turtle cake

Baking with food allergies does not need to be frustrating! Even if you can’t use certain ingredients, you can produce amazing desserts that the whole family will love.

  • Accidental ingestion of fish or a fish byproduct
  • Inhalation of dust that contains fish particles
  • Cross-contamination 

Types of Finned Fish

  • Anchovy
  • Bass
  • Catfish
  • Cod
  • Flounder
  • Grouper
  • Haddock
  • Hake
  • Halibut
  • Herring
  • Mahi Mahi
  • Perch
  • Pike
  • Pollock
  • Salmon
  • Snapper
  • Sole
  • Swordfish
  • Tilapia
  • Trout
  • Tuna
  • Walleye

Common Foods That Contain Fish

Most products that contain fish are labeled clearly, but here are a few common foods you might not expect to find fish in it:

  • Barbecue sauce
  • Bouillabaisse
  • Caesar salad and caesar dressing
  • Imitation or artificial fish
  • Worcestershire sauce
  • Fish sticks
  • Food made with fish sauce

Ingredients To Avoid

If you’ve been diagnosed with a fish allergy, it’s important that you read ingredient labels carefully to avoid accidentally ingesting any fish. As required by federal law, fish is one of the nine major allergens that must be listed in plain language on packaged foods sold in the U.S., either within the ingredient list or in a separate “Contains” statement on the package. This makes it easy to see if fish is present in a food item.  Besides the obvious names for fish, you’ll also want to avoid:

  • Fish oil
  • Fish gelatin
  • Fish flavoring

Fish Allergy Treatment

Treatment for fish allergy includes strict avoidance of the fish to which you are allergic. 

Managing Fish Allergies

The most effective way to manage fish allergies at home is simply to avoid bringing any fish or fish-containing products into the house. You should read ingredient labels carefully, make sure everyone in the household is aware of the allergy, and have a system in place in case you have to handle an allergy attack. Check out my 8 Tips to Keeping an Allergy Friendly Kitchen.

Also, stay away from seafood restaurants and fish markets, where there is a high risk of food cross-contact.

What About Iodine?

According to, “Fish allergy is sometimes confused with iodine allergy because fish is known to contain the element iodine. But iodine is not what triggers the reaction in people who are allergic to fish. If you have a fish allergy, you do not need to worry about cross-reactions with iodine or radiocontrast material (which can contain iodine and is used in some radiographic medical procedures).”

Will My Child Outgrow Their Fish Allergy?

While there have been a few reports of people outgrowing their fish allergies, most of the time, once a fish allergy is reported, it will stay with someone for the rest of their life.

Frequently Asked Questions

What is the most common fish allergy?

There is one study that shows salmon, tuna, catfish, and cod were the most common types of fish people were allergic to.

Can you be allergic to just fish?

Yes, just because you have a fish allergy does not automatically mean you’re also allergic to shellfish. There is a difference in their proteins, but it would be good to check with an allergist to rule out a shellfish allergy.

What causes sudden fish allergy?

It’s actually quite common for someone to develop a fish allergy later in life. In fact, one study shows that almost 40% of people who reported having a fish allergy didn’t have it until later in life.

Can I be just allergic to one type of finned fish?

Yes, you can be allergic just to one type of finned fish, but more than half of people who are allergic to one type of fish are also allergic to other fish, so speak to your allergist about testing for other varieties. Do not change your diet without guidance from your allergist.

While a fish allergy may seem like a shocking diagnosis to handle at first, there are steps you can take to stay safe. You may feel lost, confused, or overwhelmed, but if you look in the right spots, there’s an overabundance of support.

Living with a food allergy is totally manageable! Yes, it requires attention to detail, planning, and vigilance. It also means that certain foods must come out of your diet. But it does not mean that life as you know it will end. With some simple safety steps, you can still eat out, travel, go to parties, send your child to school or on play dates, and live a normal life. 

You can also join a Facebook group, read books, listen to podcasts, or find a blog specializing in fish allergy-friendly food. There are plenty of resources out there that will help you navigate a new diagnosis.

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