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

Tuna Allergy Test: Allergen Exposure

Tuna is a saltwater fish related to mackerel which is found in warm seas around the world and extensively fished commercially as a food fish.

It is sold fresh, frozen and canned. Fresh tuna is often sold as steaks, which are often cooked rare. Tuna steak is a popular ingredient in salads, wraps and char grilled dishes. Fresh tuna is also a prized ingredient in sushi, or sashimi where it is usually served raw.

The most sought after species for sushi is the bluefin tuna, although other species are commonly used.

Canned tuna is a popular food around the world, usually packed in brine, freshwater or oil, or in flavoured sauces. Depending on the quality of the fish it may be sold as steak, chunks or flakes. Canned tuna is a popular ingredient in salads, casseroles or as a sandwich filling.

Popular dishes containing tuna include tuna melts (sandwiches with tuna topped with melted cheese), salade Nicoise (a French salad of tuna, green beans, potatoes and eggs) and tuna burgers (served in a bun in the style of a hamburger).

Tuna is a rich source of phosphorus and protein, and a moderate source of iron.

Tuna Allergy Test: Allergen Description

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

Tuna 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 and small.

Cross-reactivity within the family Scombridae can therefore be expected, which includes tuna, mackerel and bonito.

Tuna Allergy Test: Clinical Experience

Sensitisation to fish allergen is common. Fish, including tuna, is a potential cause of food allergy and atopic dermatitis.

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

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 tuna.

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. Care must be taken when eating tuna, particularly if prepared raw as sashimi or in sushi, that the flesh has been frozen (or cooked) properly in order to kill any parasites present.

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.