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Fish Allergy - What You Need To Know

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Updated August 09, 2013

Fish allergy

Salmon is a common allergenic fish.

Chuck Young, U.S. Fish & Wildlife Service

Overview:

Pollock, salmon, cod, tuna, snapper, eel, and tilapia are among the fish that commonly trigger fish allergies. Fish allergies are similar to shellfish allergies in that they are more likely than many food allergies to start during adulthood and less likely than other allergies to be outgrown. While fish is easier than many other allergens to avoid, a fish allergy is often quite severe.

Fish Allergy Symptoms:

Fish allergy is linked to an increased risk of severe asthma in adult patients. Fish has been linked with the oral allergy syndrome (in which the mouth itches or tingles after eating an allergen) in people with occupational contact with fish. The greatest risk from fish allergies is anaphylaxis, a severe systemic reaction in which the body releases large amounts of histamine, causing tissues throughout the body to swell. This can cause life-threatening breathing, cardiac, and gastrointestinal symptoms. Anyone with a fish allergy should carry any medication prescribed by their doctor at all times.

Cross-Reactivity:

There is high allergic cross-reactivity among different types of fish, meaning that people with allergies to one type of fish are likely to have (or to develop) allergies to others. This is because of a protein (parvalbumin) that is present in many fish. For this reason, most people with an allergy to one fish are advised to avoid all fish (including eel and shark). Some fish -specifically tuna and mackerel - are considered less allergenic than others. If you would like to include some fish in your diet, ask your allergist about arranging additional allergy testing to assess what might be safe for you.

Parasites and Fish Allergies:

One allergy that may masquerade as a fish allergy is an allergy to a fish parasite called Anisakis simplex. This parasite is considered a major allergen and, like fish allergies, can cause severe allergic reactions including anaphylactic shock. If you have a severe allergic reaction after eating fish but tests come up negative, consider asking your allergist to test you for an allergy to this parasite. Note that while Anisakis larvae can be killed by freezing or cooking, they can still trigger allergies after being killed, so people with Anisakis allergies should avoid fish and shellfish altogether.

Fish Allergies and Labeling Laws:

As one of the "big eight" most common allergens in the United States, fish is covered under the Food Allergy Labeling and Consumer Protection Act (FALCPA). This requires that manufacturers label the presence of fish in clear language on food labels, either in the list of ingredients or following the word "contains" after the ingredient list. Fish is not a particularly common hidden ingredient and generally appears as its own species in ingredient lists. But people with fish allergies should learn the names of many different types of fish for maximum safety when reading labels.

Foods Commonly Containing Fish:

  • Caesar salad dressing
  • Worcestershire sauce
  • Ceviche (fish or shellfish "cooked" in an acidic citrus marinade)
  • Caviar
  • Gelatin
  • Cioppino
  • Nam pla (Thai fish sauce)
  • Bouillabaisse
  • Fumet (fish stock)
  • Surimi
  • Pissaladière
  • Omega-3 supplements (if you would like to take these, look for vegan varieties made from flaxseed or other plant-derived oils)
  • Caponata

Eating Out with Fish Allergies:

There are recorded instances of inhalation reactions due to aerosolized fish proteins, so people with fish allergies should avoid hibachi-style communal grill restaurants if fish is on the menu. Seafood restaurants and sushi bars are high risks for cross-contamination due to the close proximity of fish and non-fish items. Another source of potential cross-contamination is frying oil; if fish has been fried in oil, people with fish allergies should avoid eating any other food fried in the same oil.

Living with Fish Allergies:

Fish is an easier allergen to avoid than many of the other "big eight" allergens. It is far less pervasive in the Western diet than, for example, wheat, soy, or dairy.

That's not to say that living with a fish allergy is easy. The major challenges are avoiding high-risk situations for contact with fish and managing the risk of severe asthma (where applicable) and anaphylaxis. Reading labels for fish is reasonably simple in grocery stores. Communication in restaurants, however, is vital; higher-end restaurants, especially, may use small amounts of fish to flavor dishes that may not indicate the presence of fish on the menu. For more information, see:

Managing asthma and anaphylaxis risk both depend on communication with your doctor and keeping any prescribed medication close at hand - a rescue inhaler, in the case of asthma, and injectable epinephrine (EpiPen, TwinJect, or similar medication) in the case of anaphylaxis. For more information, see:

Sources:

Berns, Stephen H., et al. "Food Allergy as a Risk Factor for Asthma Morbidity in Adults." Journal of Asthma June 2007 44(5): 377-81.

James, J. M. & J. F. Crespo. "Allergic Reactions to Foods by Inhalation." Current Allergy and Asthma Reports June 2007 7(3): 167-74.

Moneo, Ignacio, et al. "Sensitization to the Fish Parasite Anisakis simplex: Clinical and Laboratory Aspects." Parasitology Research June 17, 2007 (Epub).

Nieuwenhuizen, N., et al. "Exposure to the Fish Parasite Anasakis Causes Allergic Airway Hyperreactivity and Dermatitis." Journal of Allergy and Clinical Immunology May 2006 117(5): 1098-1105.

Sugita, Kazunari, et al. "Oral Allergy Syndrome Caused by Raw Fish in a Japanese Sushi Bar Worker." Contact Dermatitis 56(6): 369-70.

Van Do, T., et al. "Allergy to Fish Parvalbumins: Studies on the Cross-Reactivity from 9 Commonly Consumed Fish." Journal of Allergy and Clinical Immunology Dec. 2005 116(6): 1314-20.

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