A fish allergy is a type of food allergy which occurs in people who are sensitive to some of the proteins found in fish. Common food fish such as tuna, salmon, snapper, tilapia, cod, and pollock have all been linked with allergic reactions. Fish and shellfish allergies are usually separate, which means that someone who can't eat shellfish can safely eat fish, and vice versa. The presence of an allergy to fish can be confirmed in a patient with the use of allergy testing.
Somewhat uniquely for food allergies, a fish allergy is more likely to have an onset in adulthood, and people are less likely to grow out of it over time. Because the proteins which commonly cause allergic reactions can be seen in many fish, people with these allergies are usually advised to avoid fish altogether. However, it is possible to use allergy testing to determine precisely which species cause the reaction, for people who would like the option of eating some safe fish species.
In addition to being allergic to some proteins found in fish, some people are allergic to fish parasites, experiencing an allergic reaction when they eat contaminated fish. This type of allergy is more rare, and it can be frustrating, because someone may experience allergies when eating fish one night, and not on the next, making it hard to pin down the source of the allergy without careful testing. People who are allergic to parasites may need to avoid certain fish species, and ensure that their fish is always very well cooked.
One of the most common signs of a fish allergy is oral allergy syndrome, in which the mouth and lips tingle after eating fish. People can also develop intestinal discomfort and skin irritations, and in some cases, the airways may swell and close, leading to anaphylactic shock. If any of these symptoms are experienced after eating fish, people should consult other people who ate the same meal to see if they had symptoms, which would suggest food poisoning. If no one else experienced the symptoms, it is time to see an allergist to discuss allergy testing and treatment options.
People with fish allergies should be careful about eating in restaurants which serve fish. Many people can react to aerosolized proteins, such as those which might waft off a grill, and restaurants which serve fried food can be prone to cross-contamination. Asian restaurants can also be dangerous for people with this condition, because many Asian sauces contain fish. Many Mediterranean dishes also contain fish in their ingredients, so when dining at restaurants which serve cuisine from the Mediterranean, people with a fish allergy should stress that they cannot be exposed to fish in any form. Restaurant staff are sometimes not sure about the ingredients found in a dish, and diners should be firm about asking the staff to check or to state that they are unsure about the safety of a dish.