What is fish allergy?
Allergy to fish results from a physical reaction to a protein in the fish meat. This protein is found in many types of fish, however most individuals allergic to fish react predominantly to fish belonging to the cod family. Approximately half of all individuals with fish allergy will react to all kinds of fish. Some tolerate fish species such as salmon, brown trout and freshwater fish, whilst some only react to fish such as red fish and yet tolerate cod.
The allergy-provoking agents in fish are very heat stable, which means that they do not disappear with boiling or cooking. Some sensitive individuals suffer allergic reactions if they breathe in the vapour from boiled fish, because this vapour may cause asthma symptoms.
Shellfish allergy may also be severe, and often lasts a lifetime. It should not be very difficult to avoid shellfish in the diet, and such removal constitutes no nutritional loss. It is not uncommon for non-allergic individuals to react to shellfish. Such reactions are usually due to histamine release.
There is no connection between fish allergy and allergy to shellfish.
What reactions occur in fish allergy?
Individuals with fish allergy may suffer asthma symptoms, stomach symptoms, rash and running eyes and nose.
In rare instances, a severe allergic reaction, “anaphylactic shock”, may occur, with a drop in blood pressure and breathing problems. See fact sheet on allergy.
How is fish allergy treated?
Fish allergy is treated by excluding the non-tolerated foodstuff from the diet.
Which products contain fish?
A number of ready-made foods contain fish or fish products. One example is liver pate, which may contain anchovies, but it is possible to purchase liver pate without anchovies.
Crab salad may contain fish, and crab-sticks are made from fish, not shellfish. The kind of fish found in fishcakes varies. Oyster sauce or fish sauce are produced from, amongst other things, fish and shellfish and are used as seasoning in many Asian meals. Individuals with fish allergy often tolerate cod-liver oil due to the fact that the protein has been removed.
The declaration of contents should state whether the product contains fish or ingredients derived from fish, e.g. animal fat/oil. Fish oils cause no problem for most individuals with fish allergy; however, some allergic individuals are so sensitive that they can react to minute quantities of protein found in the oil.
Who gets fish allergy?
Fish allergy usually has onset relatively early in life, but rarely before the age of one, because fish is not usually introduced into the diet of children in the first 12 months. Fish allergy is often, but not always, a lifetime allergy.
Allergy to fish is a problem in the fishing industry, where it is the cause of contact eczema and asthma symptoms.
Even though some individuals are seriously affected by fish allergy, not that many individuals are affected on a country-wide basis.