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

Salmon Allergy Test: Allergen Exposure

Salmon is an oily fish which has been widely consumed by humans for thousands of years. Other fish in the same family include trout, char, grayling and whitefish.

Salmon is caught in the wild, and also farmed around the world, with little difference between the quality of the two, although farmed salmon is generally less affected by environmental contaminants. Most wild-caught salmon is Pacific salmon, conversely most Atlantic salmon sold is from farmed fish.

The flesh ranges from white to, more commonly, an orange-red hue, which is due to the prevalence of carotenoid pigments in the krill and tiny shellfish which make up the diet of wild salmon. Pigments are often added to farmed salmon feed to produce the same effect.

Salmon is sold fresh, as well as canned, smoked (hot or cold) or brine cured. Popular serving methods include gravlax (raw salmon cured in salt, sugar and dill), lox (cured fillets of salmon), rui-be (a type of salmon sashimi), cold smoked salmon, and kippered (smoked over fruitwood). It is also eaten roasted, pan fried or grilled, and is widely available as a constituent of fishcakes, fish fingers and salmon burgers.

Salmon is rich in protein and low in fat. It is an excellent source of B vitamins, particularly B12, selenium and phosphorus, as well as a good source of copper and potassium. It is also high in omega-3 fatty acids, particularly in the case of wild-caught salmon.

Salmon roe is used in some sushi dishes, as well as raw salmon.

Salmon Allergy Test: Allergen Description

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

Salmon 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 groups seems to be moderate or even small.

Salmon Allergy Test: Clinical Experience

Sensitisation to fish allergen is common. Fish, including salmon, is a potential cause of food allergy and atopic dermatitis. A study demonstrated the prevalance of sensitivity to salmon among cod-allergic children to be around one in five.

Immediate allergic reactions may follow ingestion of even minute amounts of fish.

Symptoms can include oral allergy syndrome, generalised urticaria, facial angioedema and anaphylaxis.

Because patients react to both cooked and raw fish, it is assumed the allergens are heat-resistant. However, more recent studies indicate that patients may react differently to processed food and that allergic reactions may be species-specific.

It has been reported that some fish allergic persons can exhibit allergic symptoms due to the steam (airborne allergens) from cooking fish.

Other reactions

Acute anisakiasis as a result of the larvae of the fish parasite Anisakis simplex may occur following ingestion of undercooked or raw salmon.

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.