When most people think of food allergies, they think of immediate reactions to things like shellfish and peanuts. These allergies get the most news because they’re typically the most dangerous. Kids can’t bring peanuts to school anymore due to the risk of anaphylaxis in those who are highly allergic to them. These allergies cause a release of large amounts histamine inside the body which is the chemical that causes the blood pressure to plummet and the throat to close off, posing a threat to life. These allergies are called type 1 or immediate-type allergies. These allergies are detected by skin prick and scratch tests or blood tests measuring food-specific IgE antibodies.
It turns out, other more underrated allergies can also wreak havoc on the body. Previously largely overlooked and viewed as food “sensitivities”, now in some cases appear to be due to a different type of food allergy, called a type 4 or delayed-type allergy. While not life threatening, recent medical studies suggest these allergies are often responsible for irritable bowel syndrome (IBS), consisting of frequent belly pain with associated diarrhea and/or constipation. These allergies are detected by skin patch tests. When foods identified by patch tests are avoided in the diet, IBS symptoms often improve significantly or completely disappear.