Fish Allergy

Astoundingly, there are more than 20,000 species of finfish.  Allergists generally recommend that individuals with fish allergy avoid all fish, even though it is possible for some who are allergic to one type of fish to safely eat other types.  For example, someone might be allergic to halibut, but may regularly eat salmon without a reaction.

If you are allergic to a specific type of fish but would really like to have other varieties of fish in your diet, speak to your allergist about specific allergy testing. Do not change your diet without guidance from your allergist.

If your allergist has determined that you may eat certain types of fish, take extra precautions to avoid cross-contamination (when two foods come into contact with each other and their proteins mix) when purchasing fish from a market or dining out. There’s also the widespread issue of mislabeling of fish, as some restaurants have been found to substitute cheaper types of fish instead of what is advertised on the menu. Clearly communicate your allergy with food service staff.

Due to the increased risk for cross-contamination during food preparation, it is best to avoid seafood restaurants in general, even if you plan to order a non-fish dish. Avoid areas where fish is being cooked, as proteins may be released into the air during cooking.

As with other foods, the symptoms of a fish allergy may include hives or skin rash, nausea, stomach cramps, indigestion, vomiting, diarrhea, stuffy/runny nose, sneezing, headaches, and asthma. Symptoms may range from mild to severe. A severe allergic reaction is known as anaphylaxis, which is rapid in onset and may cause death.

Fish allergy is thought to be lifelong, and is often developed in adulthood. Results of a seafood prevalence study published in 2004 in The Journal of Allergy and Clinical Immunology concluded that fish allergy affects approximately 0.4% of the population and that 30 percent of children and approximately 66% of adults reacted to multiple types of finfish. The study also found that more women than men are allergic to fish (0.6% vs. 0.2%), and the rate of fish allergy is higher among adults than it is among children (0.5% vs. 0.2%).

Frequently Asked Questions

Do fish-allergic individuals need to avoid shellfish?

Those with fish allergy do not need to avoid shellfish, and vice-versa, because there appears to be no cross-reactivity between fish and shellfish. There is, however, the potential for cross-contamination between the two. It should also be noted that an individual can be allergic to both fish and shellfish (concomitant allergy), just as someone can be allergic to egg and peanut.

What are some hidden sources of fish?

Fish is often found in Worcestershire sauce and Caesar salad, and is sometimes found in imitation crab products in the form of surimi, a processed food made mainly from Alaskan pollack. Fish is also prevalent in Asian cuisine, which uses fish-based stock for many dishes.

Reprinted with permission from the American College of Allergy, Asthma & Immunology