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

Crayfish Allergy Test: Allergen Exposure

Crayfish are freshwater crustaceans similar in appearance, and related to, small lobsters. As with other species of crustacean, only some parts of the body are edible, mainly the tail, leg and claw meat. They are generally sold and served either whole, or as crayfish tails.

They are a popular food in many countries around the world, and are prepared in a variety of ways.

In China, crayfish became widely popular in the 1990s, and they are usually served steamed and flavoured with Sichuan pepper and hot chili. In France, dishes with a base or garnish of crayfish are frequently described as à la Nantuaise (in the style of Nantua). Crayfish, along with fried egg, is the traditional garnish for the classic dish chicken Marengo.

Crayfish have been eaten in Mexico since the Aztec period, and nowadays are commonly served boiled whole with a variety of local condiments, or alternatively added to soups, salads and tacos. In Russia and Ukraine, crayfish are a traditional appetiser served as an accompaniment to beer and liquor.

In the United States there is a popular social event known as a crawfish boil, where a large number of crayfish are boiled along with spices, potatoes and corn and served on a communal table for the assembled group to share. Hot sauce, lemons and melted butter are usually available as condiments.

In Nigeria, crayfish are usually smoked, and occasionally sun-dried, and are a major part of the national diet, particularly that of people in the southern states.

Crayfish is a good source of niacin, folate, potassium and zinc, and a very good source of protein, vitamin B12, phosphorus, copper, manganese and selenium. It is high in protein, but also relatively high in cholesterol.

Crayfish Allergy Test: Allergen Description

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

Crayfish Allergy Test: Potential Cross-Reactivity

Several studies indicate cross-reactivity between crayfish and other crustaceans including crab, shrimp and lobster.

Crayfish Allergy Test: Clinical Experience

Shellfish is one of the more common food allergies, and usually persists throughout the patient’s lifetime. The majority of people (around 60%) of shellfish-allergic people experience their first allergic reaction as adults.

Within the shellfish family, the crustacean group (shrimp, crayfish, lobster and crab) causes the greatest number of allergic reactions.

Reactions can potentially affect the skin, respiratory tract, gastrointestinal tract and/or cardiovascular system. Symptoms can be severe and potentially life-threatening, including anaphylaxis. Even very small amounts of shellfish can provoke a reaction.

Exposure to the steam from cooking shellfish has been reported to cause an allergic reaction in some cases, due to the presence of allergenic proteins in the steam.

Other reactions

Shellfish poisoning is a potential consequence of ingesting shellfish contaminated with any one of a number of toxins. Symptoms may include nausea, vomiting, abdominal pain and diarrhea; chills, fever or headache; conjunctival irritation, sneezing and rhinorrhea and even paralysis.