Will food allergies cause vomiting?

Food allergy may indeed cause vomiting, but this is neither the only manifestation of food allergy, nor is all vomiting linked to food allergy.

Not long ago, my best friend's 3-year-old child ate fresh pineapple for the first time. He bit into half of it and started retching within 20 minutes. He then vomited half of it, and a small light red rash appeared around the corner of his mouth. After going to the hospital, he was diagnosed with a pineapple allergy. The doctor said that this is a typical IgE-mediated immediate allergic gastrointestinal reaction. Response - After an allergen comes into contact with the gastrointestinal mucosa, the mucosa becomes edematous and the smooth muscles contract and spasm, which is equivalent to the sudden activation of an emergency switch to "reject aliens" in the stomach. Undigested food will naturally be excreted. In addition to vomiting, abdominal pain and diarrhea are also common gastrointestinal reactions of this type of allergy.

But don’t be fooled into thinking you have a food allergy as soon as you vomit. When I was helping with science popularization in the nutrition department of a community hospital, I met many people who mistook ordinary vomiting for allergies. The one who impressed me the most was a boy who just went to college. He said that he vomited every time he ate crayfish. He was definitely allergic to crayfish. He is allergic to shrimp. After careful questioning, he found out that every time he ate crayfish, he had to drink more than 3 bottles of iced Coke, and he always ate until he could not stand up. Finally, the allergens were checked and it was completely normal. The vomiting was purely a gastric cramp caused by alternating hot and cold + overeating, and had nothing to do with allergies.

On the other hand, it is also a misunderstanding that "allergy will definitely cause vomiting". I have met a girl who is allergic to peach hairs. Every time she touches peaches, her eyes will become swollen and her throat will become tight, without any nausea at all. Some people's allergies only manifest themselves as chronic diarrhea that lasts for several days, and they will not even vomit. In fact, the symptoms of allergies vary greatly among different people, and there is no unified standard template.

If you eat a new food that you have not tried much before and suddenly vomit within 1-2 hours, accompanied by itchy skin, rash, throat congestion, difficulty breathing, etc., it is most likely caused by allergies, and you need to stop eating immediately. If the symptoms are serious, seek medical attention immediately. If there is only vomiting and no other discomfort, and there have been no problems with eating the same food before, then it is probably due to overeating, eating cold food, or overeating, so there is no need to be too anxious.

You don’t need to think too much about allergies if you vomit once in a while, but if you experience vomiting + other allergy-related symptoms after eating the same food multiple times, don’t take it seriously. It’s best to record your dietary history and do a professional allergen screening. It’s safest to avoid pitfalls in advance.