Allergy Types: Food Allergies: Fish Allergy
Finned fish can cause severe allergic reactions (such as anaphylaxis). Therefore it is advised that people with fish allergy have quick access to an epinephrine auto-injector (such as an EpiPen®, Auvi-Q™ or Adrenaclick®) at all times. This allergy usually is lifelong. Approximately 40 percent of people with fish allergy experienced their first allergic reaction as adults. To prevent a reaction, strict avoidance of fish and fish products is essential. Always read ingredient labels to identify fish ingredients.
Salmon, tuna and halibut are the most common kinds of finned fish to which people are allergic. More than half of all people who are allergic to one type of fish also are allergic to other fish, so allergists often advise their fish-allergic patients to avoid all fish. If you are allergic to a specific type of fish but want to have other fish in your diet, talk to your doctor about the possibility of allergy testing for specific fish.
Finned fish and shellfish do not come from related families of foods, so being allergic to one does not necessarily mean that you must avoid both.
The federal Food Allergen Labeling and Consumer Protection Ac (FALCPA) requires that all packaged food products sold in the U.S. that contains fish as an ingredient must list the specific fish used on the label.
Read all product labels carefully before purchasing and consuming any item. Ingredients in packaged food products may change without warning, so check ingredient statements carefully every time you shop. If you have questions, call the manufacturer.
As of this time, the use of advisory labels (such as “May Contain”) on packaged foods is voluntary, and there are no guidelines for their use. However, the FDA has begun to develop a long-term strategy to help manufacturers use these statements in a clear and consistent manner, so that consumers with food allergies and their caregivers can be informed as to the potential presence of the eight major allergens.
It has been estimated that there are upwards of 20,000 species of fish. Although this is not an exhaustive list, allergic reactions have been commonly reported to:
- Mahi Mahi
Some Unexpected Sources of Fish
- Caesar salad and Caesar dressing
- Worcestershire sauce
- Imitation or artificial fish or shellfish (surimi, also known as “sea legs” or “sea sticks,” is one example)
- Barbecue sauce
- Caponata, a Sicilian eggplant relish
Note: This list highlights examples of where fish has been unexpectedly found (e.g., on a food label for a specific product, in a restaurant meal, in creative cookery). This list does not imply that fish is are always present in these foods; it is intended to serve as a reminder to always read the label and ask questions about ingredients before eating a food that you have not prepared yourself.
To evaluate whether you have an allergy, your doctor may:
- Ask detailed questions about signs and symptoms
- Perform a physical exam
- Have you keep a detailed diary of symptoms and possible triggers
If you have a food allergy, your doctor may:
- Ask you to keep a detailed diary of the foods you eat
- Have you eliminate a food from your diet (elimination diet) — and then have you eat the food in question again to see if it causes a reaction
Your doctor may also recommend one or both of the following tests:
- Skin test. Your skin is pricked and exposed to small amounts of the proteins found in potential allergens. If you’re allergic, you’ll likely develop a raised bump (hive) at the test location on your skin. Allergy specialists usually are best equipped to perform and interpret allergy skin tests.
- Blood test. A blood test that’s sometimes called the radioallergosorbent test (RAST) can measure your immune system’s response to a specific allergen by measuring the amount of allergy-causing antibodies in your bloodstream, known as immunoglobulin E (IgE) antibodies. A blood sample is sent to a medical laboratory, where it can be tested for evidence of sensitivity to possible allergens.
If your doctor suspects your problems are caused by something other than an allergy, you may need other tests to identify — or rule out — other medical problems.
Several antagonistic drugs are used to block the action of allergic mediators, or to prevent activation of cells and degranulation processes. These include antihistamines,glucocorticoids, epinephrine (adrenaline), theophylline and cromolyn sodium. Antileukotriene agents, such as montelukast (Singulair) or zafirlukast (Accolate), are FDA approved for treatment of allergic diseases. Anti-cholinergics, decongestants, mast cell stabilizers, and other compounds thought to impair eosinophil chemotaxis, are also commonly used. These drugs help to alleviate the symptoms of allergy, and are imperative in the recovery of acute anaphylaxis, but play little role in chronic treatment of allergic disorders.
Desensitization or hyposensitization is a treatment in which the person is gradually vaccinated with progressively larger doses of the allergen in question. This can either reduce the severity or eliminate hypersensitivity altogether. It relies on the progressive skewing of IgGantibody production, to block excessive IgE production seen in atopys. In a sense, the person builds up immunity to increasing amounts of the allergen in question. Studies have demonstrated the long-term efficacy and the preventive effect of immunotherapy in reducing the development of new allergy. Meta-analyses have also confirmed efficacy of the treatment in allergic rhinitis in children and in asthma. A review by the Mayo Clinic in Rochester confirmed the safety and efficacy of allergen immunotherapy for allergic rhinitis and conjunctivitis, allergic forms of asthma, and stinging insect based on numerous well-designed scientific studies. In addition, national and international guidelines confirm the clinical efficacy of injection immunotherapy in rhinitis and asthma, as well as the safety, provided that recommendations are followed.
A second form of immunotherapy involves the intravenous injection of monoclonal anti-IgE antibodies. These bind to free and B-cell associated IgE; signalling their destruction. They do not bind to IgE already bound to the Fc receptor on basophils and mast cells, as this would stimulate the allergic inflammatory response. The first agent of this class is omalizumab. While this form of immunotherapy is very effective in treating several types of atopy, it should not be used in treating the majority of people with food allergies.
A third type, sublingual immunotherapy, is an orally administered therapy that takes advantage of oral immune tolerance to non-pathogenic antigens such as foods and resident bacteria. This therapy currently accounts for 40 percent of allergy treatment in Europe. In the United States, sublingual immunotherapy is gaining support among traditional allergists and is endorsed by doctors treating allergy.
Allergy shot treatment is the closest thing to a ‘cure’ for allergic symptoms. This therapy requires a long-term commitment.
An experimental treatment, enzyme potentiated desensitization (EPD), has been tried for decades but is not generally accepted as effective. EPD uses dilutions of allergen and an enzyme, beta-glucuronidase, to which T-regulatory lymphocytes are supposed to respond by favouring desensitization, or down-regulation, rather than sensitization. EPD has also been tried for the treatment of autoimmune diseases but is not approved by the U.S. Food and Drug Administration or of proven effectiveness.
Systematic literature searches conducted by the Mayo Clinic through 2006, involving hundreds of articles studying multiple conditions, including asthma and upper respiratory tract infection, showed no effectiveness of homeopathic treatments and no difference compared with placebo. The authors concluded that, based on rigorous clinical trials of all types of homeopathy for childhood and adolescence ailments, there is no convincing evidence that supports the use of homeopathic treatments.
If you’re allergic to one kind of fish, your doctor may have told you to avoid others. Here’s what to look out for.
Surprising Sources of Fish
Foods that may contain anchovies
- Worcestershire sauce
- Barbecue sauces made with Worcestershire
- Caesar salad and Caesar dressing
- Caponata (Sicilian eggplant relish)
Other foods that have fish:
- Caviar and fish roe (fish eggs)
- Artificial fish like surimi, an imitation crabmeat, sometimes used in sushi
- Fish sauce, oils, and gelatin
4 Tips for Avoiding Fish
- Stay out of seafood restaurants. Even if you order the beef, bits of fish from a shared spatula, cooking oil, or grill can get in your food. That kind of cross-contact can happen in any eatery that uses a lot of fish or fish ingredients, including many ethnic restaurants.
- Don’t shop for or cook fish. Let someone else do it. You may get a reaction to touching fish or being in an area where it’s being cooked.
- Ask your doctor if any fish or shellfish is safe to eat. Don’t try out a fish on your own, though. Fish can cause severe allergic reactions.
- Read labels. Other foods — as well as lotions, cosmetics, and medicine — may have fish in them.
Keep the following in mind:
- Fish protein can become airborne in the steam released during cooking and may be a risk. Stay away from cooking areas.
- If you have seafood allergy, avoid seafood restaurants. Even if you order a non-seafood item off of the menu, cross-contact with fish is possible.
- Ethnic restaurants (e.g., Chinese, African, Indonesian, Thai and Vietnamese) are considered high-risk because of the common use of fish and fish ingredients and the possibility of cross-contact, even if you do not order fish.
- Avoid foods like fish sticks and anchovies. Some individuals with fish allergy make the mistake of thinking that such foods don’t “count as real fish.”
- Many people who are allergic to fish or shellfish are allergic to more than one kind. Get tested and have your allergies confirmed by a physician so that you know for sure which foods to avoid.
- The protein in the flesh of fish most commonly causes the allergic reaction; however, it is also possible to have a reaction to fish gelatin, made from the skin and bones of fish. Although fish oil does not contain protein from the fish from which it was extracted, it is likely to be contaminated with small molecules of protein and therefore should be avoided.
- Carrageenan, or “Irish moss,” is not fish. It is a red marine algae that is used in a wide variety of foods, particularly dairy foods, as an emulsifier, stabilizer and thickener. It appears safe for most individuals with food allergies.
- Allergy to iodine, allergy to radiocontrast material (used in some radiographic procedures), and allergy to fish are not related. If you have an allergy to fish, you do not need to worry about cross reactions with radiocontrast material or iodine.
Most allergic reactions respond well to medications.
- Hives, swelling, breathing difficulties, even anaphylaxis often improve and disappear in minutes to hours.
- Some rashes take several days to heal.
- A doctor may want to monitor the patient for a few hours.
- A dangerous allergic reaction may warrant an overnight stay in the hospital.
Allergic reactions will continue with continued exposure to the allergen or trigger.
- Avoid any triggers that cause an allergic reaction.
- Ingested, inhaled, or injected allergy triggers may take days for the body to eliminate.
- Continued medical therapy is necessary for continued exposure.
People may be referred to an allergy specialist if they continue having reactions.
Complications of fish allergy can include:
- Anaphylaxis. This is a life-threatening allergic reaction.
- Atopic dermatitis (eczema). Food allergy may cause a skin reaction, such as eczema.
- Migraines. Histamines, released by your immune system during an allergic reaction, have been shown to trigger migraines in some people.