One reason why people are allergic to shrimp is that shrimp meat contains a high content of protein. Similarly, aquatic products, fish with low protein content are less allergic than shellfish.

Allergy to something is genetic and difficult to solve. Theoretically, any food containing protein may cause allergies.

For human body, protein contained in shrimp belongs to foreign protein. Foreign protein like this is an antigen to people, and like bacteria and viruses, it will be recognized by the immune system as an in vitro antigen, which will immediately trigger a series of immune reactions.

Some people with sensitive constitution are particularly sensitive to different proteins, and the immune system often overreacts, which is commonly known as allergy. Mild can cause urticaria, and severe can even lead to shock and death.

Another reason is that some people eat fresh fish and shrimp with excessive histamine because of their natural lack of enzymes that decompose histamine, which will cause allergies.

As for the degree of allergy, it is much more. What is lighter is that the shrimp is itchy and painful all over, and even the shrimp will break out in a rash when it is touched by hands.