Standard label for children suffering from fish allergy. (Photo: Stockfile/FIS)
Fish allergy seems to be on the rise. Why?
Monday, March 13, 2017, 07:00 (GMT + 9)
Although fish allergy is less common among the general population than other types of food allergies, it is a common cause of anaphylaxis, a life-threatening allergic reaction that appears fast, impairs breathing, and may send the body into shock.
The cases of allergy increase every year, a third of the population in Europe suffers from some form of allergy. In Spain more than 10 million people suffer from allergies and the number of people with allergy grows 5 per cent each year in Central Catalonia. Why does this increase take place?
Allergy is caused because our immune system reacts to a substance that is generally harmless (like pollen or some food). The body identifies that this substance is a threat and produces an exaggerated response to that stimulus.
About 30 per cent of adults and 40 per cent of young people present allergy to certain plants. It is not one but there are several factors involved in the increase of allergies. Changes in climate, excess hygiene, genetic factors, changes in food.
Increases in allergies occur mainly in all countries being industrially developed, from Europe to the United States. The allergy pattern is also changing. In principle, asthma and allergic rhinitis or hay fever increased. Recent studies confirm an increase in food allergies, especially in children. For example, in the UK up to 50 per cent of children are diagnosed with an allergic disease. The researchers say that the increase in cases of allergies is not due to a single factor but to a number of factors.
Unlike other food allergies, which are usually first seen in babies and toddlers, a fish allergy may not become apparent until adulthood. In a study, up to 40 per cent of people who reported a fish allergy had no problems with fish until they were adults.
Having an allergy to fin fish (such as tuna, halibut or salmon) does not mean that the person is also allergic to shellfish (shrimp, crabs and lobsters). While some allergists recommend that people with allergies to fish should avoid eating all fish, it may be possible for someone who is allergic to one type of fish to safely eat other types. If you are allergic to a specific type of fish, your allergist can help you determine if other varieties can be safe to eat.
Symptoms of fish allergy
As with other food allergies, the symptoms of a fish allergy can range from mild to severe. They include:
- Urticaria or a rash;
- Nausea, stomach cramps, indigestion, vomiting and/or diarrhea;
- Clogged or stuffy nose and/or sneezing;
- Anaphylaxis (less common), a life-threatening reaction that impairs breathing and may cause the body to go into shock.
In the skin prick test, a small amount of a liquid is placed containing the fish protein being tested on the back or forearm, which is then pricked with a small sterile probe to allow the liquid to penetrate on the skin. If a raised reddish spot is formed within 15 to 20 minutes, that may indicate an allergy.
In the blood test, a blood sample is sent to a laboratory to check for the presence of immunoglobulin E antibodies against the fish protein being tested.
If these tests are not definitive, the allergist may order an oral food challenge. Under medical supervision, the patient will eat small amounts of fish or a fish product to see if a reaction develops. Due to the possibility that a reaction could be severe, this test is carried out in the allergist's office or in a food challenge centre with emergency equipment and medication at hand.
Management and Treatment
Managing a fish allergy includes strict avoidance of fish to which you are allergic. Doctors generally advise people who are allergic to a type of fin fish to avoid all types.
Fish is one of eight allergens with specific labelling requirements under the Food Allergen Labelling and Consumer Protection Act of 2004. Under this law, manufacturers of packaged food products sold in the United States and containing fish or a product having fish as an ingredient must identify the ingredient on the label, in clear language, identifying the specific type of fish used.
Many prepared foods contain fish in some way. Fish is a common ingredient in Worcestershire sauce and Caesar salad and is found in imitation crab products in the form of surimi, a processed food made mainly from Alaska pollock. Fish is also prevalent in Asian cuisine, which uses the fish base for many dishes.
While an allergy to fish protein is more common, it is possible to be allergic to fish gelatine (made from fish skin and bones). People with a fish allergy should consult their allergist before taking dietary supplements of fish oil.
Source: ACCAI - American College of Allergy, Asthma & Immunology