It is also common in western countries like Europe, the USA, and even found in Australia (6). Shellfish allergy is prevalent among adults and children in Asian countries. Depending on the country and its dietary habits, the prevalence of shellfish allergy is reported to range from 1.3% to 5.2% (8). Shellfish allergy is one of the common food allergies, which may continue for a long time, usually persisting till adulthood. The major shellfish allergen tropomyosin is present in the pincer and tail of crabs (6) while arginine kinase is obtained from crab leg muscles (7). Most of the characterized shellfish allergens are present in the edible body parts (muscle regions) of different shellfish species. A study by Baylon (2007) revealed that larvae (zoea and megalopa) are highly sensitive to low temperature (20 ☌) and all the developmental stages are intolerant to low salinity (<15%). The temperature at the bottom of the water is directly related to the size and inversely related to the abundance of crab (2). HabitatĬrabs are generally found throughout the polar region, which includes the Bering Sea, the Arctic Ocean, the western North Pacific coast of Asia, and also the northern Atlantic Ocean. The spawning season of crab is September and March in primiparous and multiparous females respectively and the main hatching season is early spring in both primiparous and multiparous females (3). Males are larger in size compared to the females with the maximum carapace width around 95 mm in females and 150 mm in males in Atlantic Canada (2). They are stenothermal subarctic species, living in the cold water of temperature around –1.5 to 4 degrees Celsius. Snow crabs ( Chionoecetes opilio) are the most processed and widely used species from the family Oregoniidae (1). In sensitized individuals, it is advised to avoid crab meat intake and exposure to crab meat (handling) to prevent crab allergic reactions. The most important pan-allergen in crab and other shellfish is tropomyosin, which causes cross-reactivity with other crustaceans, mollusks, mites, cockroaches, and parasites. Major allergens identified in crab are tropomyosin and arginine kinase. In Canada, snow crab allergen is found to be one of the major causes of respiratory allergic symptoms, such as asthma and rhinitis in fishermen and crab industry workers. Allergens in crabs can induce oral food allergy symptoms and also reactions including urticaria, angioedema, eczema, gastrointestinal symptoms (diarrhea, vomiting), systemic reactions (anaphylactic shock), and respiratory symptoms. The main route of crab allergen exposure is ingestion of crab meat and the secondary route is occupational exposure (inhalation or contact). Worldwide crabs are widely processed and commercially used shellfish species.Crab allergy prevalence is rising in Asian countries like China, Taiwan and Singapore.