Is it a food allergy or food intolerance?

That is an allergic reaction and you should stop eating crabs and foods that may contain crab products. I strongly suggest you visit your doctor because your physician may want to prescribe an epi-pen to you in case of an emergency. Allergic reactions are nothing to play with because they usually worsen with each exposure to the allergen.

A food intolerance would only interact with the digestive tract. This is because your body is unable to break down a specific molecule found in that particular food. For example lactose intolerant individuals experience diarrhea and lots of abdominal pain because their body cannot breakdown something called lactose (which is found in dairy products).

There is much understanding about these terms and they are frequently confused. A true food allergy occurs when the immune system mistakes something we eat as a threat, and reacts accordingly. An allergic reaction may occur within a few minutes of ingesting an allergen, or take as long as an hour to develop. Most reactions are mild, as with a rash or hives, but a severe reaction can cause anaphylactic shock, a life-threatening condition in which the lungs constrict, restricting breathing. While the symptoms of food intolerance are much more delayed, less dramatic, and lifestyle threatening rather than life threatening. People with food intolerance typically catch viruses easily, may have dry skin, hair and nail problems and tire easily.