If you know you are at risk for a life-threatening anaphylactic reaction to fish or shellfish, you simply have to eliminate them from your diet. If you have "just a touch" of shellfish allergy, there are steps you can take to make risk of sneezing, wheezing, tearing, and hives less likely from overindulgence or accidental ingestion.
Many species of fish are especially rich in the amino acid histidine. The amino acid histidine can degrade into the compound histamine (the irritant chemical you take antihistamines to stop) if fish are not refrigerated promptly after catch.
This problem is worst with tuna and mackerel. If these species are not chilled to stop bacterial growth, bacteria on and in the flesh of the fish release an enzyme called decarboxylase that transforms the histidine into the irritant histamine. So, one way to minimize a fish allergy is simply to make sure you don't eat spoiled fish.
Fish that is high in histamine will have a peppery taste even if it's not seasoned. If refrigeration simply is not available, treating the fish with lime juice will counteract the enzyme that releases histamine.
Another way to achieve fish and shellfish allergy relief is to minimize cross-sensitivities.
People who are allergic to fish or shellfish tend also to be allergic to the preservatives BHA and BHT. Reduce exposure to BHA and BHT, and you reduce the severity of a concurrent reaction to fish or shellfish.
Also, if you are allergic to one kind of shellfish, you're probably allergic to them all. Remember, not all shellfish (at least in terms of their potential to cause allergy) have shells. The list of related allergenic foods includes but is not limited to:
- Sea Urchins
- Squid/Calamari and
The allergens in shellfish and related foods are still in the food after cooking.
Many times allergy sufferers react not to the fish or shellfish itself but to the Anisakis larvae infesting the fish. A European study found that in Spain, 35 per cent of people who thought they were allergic to fish were really only allergic to Anisakis.
Even though freezing kills the parasite, even cooked dead parasites can cause an allergic reaction. Serving fish with ginger may reduce symptoms, but to avoid this particular allergy, you need to buy your fish from an honest and knowledgeable fishmonger.
Finally, it's possible to have a "fish" allergy provoked by eating chicken. Chicken who fed fish meal (so that they lay DHA-rich eggs) can pick up the Anisakis parasite and pass it on to unlucky diners. Cooking the chicken well unfortunately does not stop allergies to the parasite. Anisakis allergies have not, however, been reported from eating DHA-rich eggs.