Unlike some other food allergies, once a person has developed an allergy to seafood it is likely to be with them for the rest of their lives. An estimated 7 million Americans (2.3% of the population) have some sort of seafood allergy, whether to fish, shellfish, or both. Approximately 60% of those with fish allergies and 40% of those with shellfish allergies have experienced them since childhood. Although a seafood allergy can develop in adults at any time, it most commonly appears between ages 40 and 60, according to research published in the Journal of Allergy & Clinical Immunology.
Lead researcher of the fish allergy study, Dr. Scott H. Sicherer, of New York’s Mount Sinai School of Medicine, said of allergic reactions to seafood that "most persons have multiple reactions, and that reactions often include severe symptoms." Severe symptoms can include low blood pressure and anaphylactic shock, in which the throat swells, severely restricting or blocking the passage of air to the lungs. Even more minor reactions such as hives, swelling and skin reactions can trigger a more serious asthma attack. Other symptoms may include dizziness, tightness in the chest, vomiting, and diarrhea. Allergic reactions usually happen within minutes of contact or ingestion, however, it may also be possible to have a delayed reaction a few hours later.
Facts about seafood allergies
The term "seafood" applies to fish with fins (such as tuna, salmon and cod), and shellfish, a classification that encompasses both crustaceans (shrimp, crab, lobster) and mollusks (clams, oysters, scallops). The allergy is caused by the body’s immune system overreacting to the specific proteins present in seafood that are called amines.
Among some of the facts about seafood allergies are the following:
What you should avoid to prevent an allergic reaction to seafood
Experts at Food Allergy Research and Education (FARE) advise that those who have a fish allergy avoid any type of contact with fish. This includes avoiding seafood restaurants, fish markets and anywhere fish is being cooked. There is a high risk of cross-contamination in the kitchen of a seafood restaurant, even if you order a dish that does not contain seafood. And the proteins in fish that cause allergic reactions may become airborne as it is cooking.
Fish is used for flavoring a variety of prepared foods, so be sure to read the labels on any products you buy in the supermarket to ensure that they do not contain any fish, including the following: Worcestershire sauce, miso paste, salad dressing, imitation fish or shellfish, pasta sauce, pet food, barbecue sauce and meatloaf. Asian food also often contains fish as a base for flavoring sauces, so be cautious when eating in an Asian restaurant.
Although fish oil supplements may seem like something to avoid, many people with fish allergies have no reaction to these supplements. However, first check with your doctor to ensure that it is a safe option for you.
Those who are allergic to one type of seafood may be able to tolerate another. For example, someone allergic to shrimp (crustacean) may be able to eat salmon (finned fish), and someone who has no problem with clams (mollusk) may be allergic to lobster (crustacean).
If you suspect you may have a seafood allergy, it is best to have reliable allergen specific tests performed to confirm or rule out potential allergy triggers. This way, you can be given a prescription for an Epi-pen (epinephrine) that can save your life during a severe allergic reaction.