Herring is a food which may result in allergy symptoms in sensitised individuals.

Herring Allergy Test: Allergen Exposure

Herring has been a staple human food for around 5,000 years. There are a number of different species, the majority of which belong to the Clupeidae family. Adult herring are harvested for their flesh and eggs, and they are often used as baitfish.

Herring are consumed fresh, as well as being preserved by drying, salting, pickling, fermenting, curing or smoking. Smaller herrings are often canned and sold under the name “sardines”.

Cold smoked herring are sold in the U.K. as kippers, a popular breakfast food. Herring is also a popular breakfast food in the Philippines, where it is served dried accompanied by garlic flavoured rice and eggs. Very young herring are called whitebait and are eaten whole as a delicacy, often fried in a light batter.

In Sweden, a traditional soup is made from herring. Pickled herring is popular in Scandinavian, Jewish, Northern and Eastern European cuisines.

Cured herring served with raw onion is a delicacy in the Netherlands, produced from the first seasonal catches of herring around late spring to early summer.

The roe from herring is a delicacy in Japan known as kazunoko.

The fish is a rich source of vitamin B12, as well as being high in niacin, vitamin B6, vitamin D, and phosphorus, and containing moderate levels of zinc and other B vitamins. It is an excellent source of omega-3 fatty acids. Herring is high in protein and low in fat, containing no carbohydrates.

Herring Allergy Test: Allergen Description

No specific allergens present in herring have been characterised, although a number of proteins have been identified.

Herring Allergy Test: Potential Cross-Reactivity

Species within groups of fish, like Gadiformes (examples: codfish and hake) and Scombroid fishes (examples: mackerel and tuna) seem to share allergenic components. The overlap of allergen specificity between the groups seems to be moderate or even small.

Cross-reactivity within the order Clupeiformes can therefore be expected, which includes herring, sardines and anchovies.

Herring Allergy Test: Clinical Experience

Specific IgE-antibodies to herring have been shown in several studies of patients with atopic dermatitis, asthma and other symptoms.

Another study of 225 allergic children showed IgE antibodies to herring in 14% of participants. It was also found that the reactions decreased in proportion to increasing age.

Contact dermatitis caused by herring has also been reported.

Other reactions

Anisakiasis, or herring worm disease, is a parasitic disease caused by nematodes (worms) that attach to the wall of the esophagus, stomach, or intestine.

Symptoms can include abdominal pain, nausea, vomiting, abdominal distention, diarrhea, blood and mucus in stool, and mild fever. Allergic reactions with rash and itching, and infrequently, anaphylaxis, can also occur.

Fish allergy is sometimes confused with a reaction to histamine in spoiled fish.

Pacific and Atlantic herring are susceptible to contamination from environmental pollution, such as by PCBs, PBDEs, mercury, and listeria. Eating contaminated herring eggs may also cause cholera.