What are the foods that cause allergies?

Milk, eggs, peanuts, nuts (walnuts, almonds, cashews, etc.), soybeans, wheat, fish, crustaceans (shrimp, crab, shellfish).

I just met a 2-year-old child in the clinic last week. My grandma wanted to give the child some nutrition, so she steamed a small crab. The child only licked a mouthful of the juice from the crab legs. Within two minutes, the area around his mouth turned red and he kept scratching. He also started coughing and wheezing. He was sent to the emergency department and was prescribed anti-allergic drugs before he recovered. It was a typical instant allergy to crustaceans.

Don’t think that only these eight categories can cause allergies. I have met college students who are allergic to enoki mushrooms before. Every time they eat the cold enoki mushrooms in the cafeteria, they get wheezes all over their body. At first, I thought it was a problem with garlic or vinegar. I tried pure enoki mushrooms alone several times before I was able to determine the allergen. There are many similar scattered allergens. Peach, mango, buckwheat, and kiwi are all relatively common, and the high-risk allergens in people in different regions are not the same. For example, the proportion of East Asian people allergic to peach hair and mango is much higher than that of European and American people. Mustard allergy, which is common in Europe and the United States, is rare in China.

There are a lot of statements about food allergies on the Internet, and they are quite controversial. For example, many people say that "allergies in childhood will get better when they grow up." This is indeed true in some cases, such as milk and egg allergies in infants and young children. About 60% of children will gradually build up tolerance by the age of 6, and they will be fine if they eat normally. However, allergies to peanuts, tree nuts, and seafood will most likely follow people throughout their lives. Blindly waiting for "it will get better when they grow up" may lead to danger. Some people also say that "allergenicity disappears when food is cooked thoroughly." This cannot be generalized. The whey protein in milk will indeed destroy the structure and reduce allergenicity after being heated to high temperature for a long time. However, the allergenic protein of peanuts is particularly stable. Whether it is fried, boiled or ground into peanut butter, it is still sensitizing, and people with allergies cannot touch it.

There is also a situation that surprises many patients. There was a 32-year-old female patient who was fine after eating mangoes for more than 20 years. Some time ago, she stayed up late for a week to catch up on projects. After eating a small mango, her face swelled to the point that she could not open her eyes. The specific IgE test showed that she was indeed allergic to mango. To put it bluntly, her immune status was messed up. Things she was not allergic to before may suddenly cause sensitization, so don’t think that "if you ate it fine before, you will never be fine."

Oh, by the way, I also want to mention that many people confuse food intolerance with allergies. For example, after drinking milk and having diarrhea, they say they are allergic to milk. In fact, more than 90% of them are lactose intolerance. It means that the body lacks lactase and cannot digest the lactose in milk. It is completely different from allergies mediated by the immune system. If you really develop a rash, difficulty breathing, or palpitation quickly after eating a certain food, that is a typical allergic reaction. You must go to the hospital as soon as possible and don't force yourself to bear it.