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

Clam Allergy Test: Allergen Exposure

Clam is the common name for a number of closely related bivalve molluscs, generally those which are edible. They are identifiable by their structure, which comprises two hard shells joined by a flexible hinge, encasing a soft body. Depending on the species, clams range in size from 1 or 2 cm up to 15cm for the largest variants.

They have been consumed by humans for thousands of years, and are a popular food in a number of cuisines, including those of North America, Japan, Europe, India and the Caribbean.

Whole clams are available fresh and alive or sometimes frozen. The shucked form (with both of the shells removed) is widely available fresh, frozen (either raw or precooked), or canned.

Clams are eaten raw, steamed, boiled, baked or fried. In North America they are an important ingredient in a number of dishes including clam chowder, clam cakes, New England clam bake and various types of ceviche.

In Japan, clams are often served as part of a mixed seafood dish. They are also used in hotpots, added to miso soup and simmered in soy sauce and mirin.

In Italy clams are often added to pasta dishes, with one of the best known being spaghetti vongole. They may also be added to salads along with other types of seafood.

In the Kerala region of India clams are used to make curries and fried with coconut.

Clams are high in protein, low in fat, and are also an excellent source of iron, zinc, selenium, and vitamin B12.

Clam Allergy Test: Allergen Description

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

Clam Allergy Test: Potential Cross-Reactivity

Cross-reactivity has been demonstrated between clam, krill and oyster.

Cross-reactions are found between molluscs, especially within the same class (bivalves, cephalopods or gastropods).

Therefore those allergic to bivalves (clams, mussels, oysters, and scallops) are likely to react to other bivalves, while those reacting to gastropods (abalone, limpets, snails, winkles and whelks) are likely to react to other gastropods.

Clam Allergy Test: Clinical Experience

Occupational asthma and food allergy caused by clam have been reported.

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.

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

Seafood may contain high levels of histamine.

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.