Fish allergy is a type of food allergy. Food allergy occurs when the body’s immune system wrongly identifies a food as a threat. When this happens, the body releases chemicals, such as histamine, in response. It is the release of these chemicals that causes symptoms.
Fish allergy refers to fish that have fins such as cod, plaice, haddock, herring, trout, salmon and tuna – as opposed to shellfish – and all types have the potential to cause allergic reactions. People who are allergic to one type of fish have a high chance of reacting to others as they contain similar proteins.
Allergy to fish often begins in childhood and may be lifelong. Some children outgrow their fish allergy but it’s not clear how likely this is to happen or at what age. Some research suggests it’s fairly common for children to outgrow their allergy in their teens. Fish allergy can also begin in adulthood.