food allergy dermatitis

Food allergy dermatitis is an inflammatory reaction of the skin mediated by the immune mechanism after eating specific foods. As long as the allergens are removed in time and standardized intervention is performed, the vast majority of patients can fully recover within 1 to 2 weeks without leaving skin scars or long-term sequelae.

I just met a 19-year-old girl in the clinic two weeks ago. She had a dinner with friends and ate half a box of mango pancakes. She felt a little itchy around her mouth that night. She thought it was because she had a fever and didn't take it seriously. She applied some aloe vera gel that she had at home and went to bed. However, when she woke up the next day, her mouth was swollen and turned half a circle, and there were a dense number of small blisters around it. It was so itchy that she couldn't sleep in the middle of the night, and even the mask hurt. When she came, she was still asking if she could never eat mangoes again? In fact, it’s not necessarily true. It’s not as exaggerated as everyone thinks.

Oh, by the way, let’s clear up a common misunderstanding first: Many people think they have food allergy dermatitis because they develop red pimples the next day after eating hot pot, their faces are swollen after eating too salty pickled food, or they even get a rash after eating too much seafood. In fact, it is not. Strictly speaking, only when the immune system treats originally harmless food as an invading "enemy" and releases inflammatory factors that damage skin cells when attacking, can this be regarded as allergic-induced dermatitis. Most of the things mentioned before are irritating reactions to food, which will disappear on their own within two days after stopping. Of course, some clinicians in the industry will classify all food-induced skin inflammations into this category in order to facilitate patients' understanding. This is essentially to reduce communication costs, which is not wrong.

The allergens encountered in daily consultations are also quite interesting. For children, the most common food supplements are milk, eggs, and peanuts. For adults, most of them are "fresh food contestants" such as mango, pineapple, and nuts. There are also many hidden in the ingredient list that you can't even notice. Last month, a young man who worked in the field of design came for a follow-up consultation. He said that the eczema on his arms had been recurring for almost a month. He had stopped using any irritating skin care products and applied medicine on time, but it was not easy to deal with. Finally, after carefully reviewing his diet for half a month, he discovered that the instant coffee he brewed every day to catch up on projects contained cashew nut creamer to which he was allergic. After stopping the coffee, it completely disappeared within three days.

The symptoms of an attack are not precise. Some people have a rapid attack. The area around their mouth will start to become red and itchy half an hour after eating. In severe cases, there will be wheals and yellow water oozing.； There are also people who have delayed onset of the disease, with erythema and papules slowly appearing all over their body after 1 to 3 days after eating. This is the most annoying, as most people never think that it was caused by what they ate two days ago. I have also encountered an even more exaggerated case. A girl was allergic to barley. After eating a bowl of light salad with barley sprout powder, she only developed a rash on her feet on the third day. At first, she thought it was an insect bite, and it took her almost a week to find out the cause.

As for whether to check allergens, there are actually different voices in the industry. Some doctors think that if the attack only occurs once in a while and they can clearly find the suspicious trigger, there is no need to spend hundreds of dollars for examination. They can just go back and avoid it for 3 to 6 months. It is a waste of money. ； However, some allergist doctors believe that patients who have repeated attacks and cannot find clear triggers must be investigated, especially cross-allergies. For example, many people who are allergic to mugwort and ragweed will also be allergic to peaches, mangoes, and lychees. If you only avoid mangoes that have a clear attack but not peaches, they will still relapse. My own experience is that if you have more than two attacks a year and you really can’t figure out the cause, go get a serum-specific IgE test to avoid blindly restricting food and eventually not being able to keep up with normal nutrition.

Don't mess with it if it does happen. I've seen too many people apply some grass ointment or ancestral anti-itch ointment blindly. It was just a slight red spot at first, but after applying it, it swelled into a pig's head and oozed yellow water. If it is mild, you can apply a weak glucocorticoid ointment locally, such as desonide cream, twice a day for three to five days. There is no need to talk about hormone discoloration. There is no dependence on weak ointments for short-term use, and they are 100 times safer than those "pure natural ointments" with unknown ingredients. If the itching is severe, take a tablet of loratadine or cetirizine. Don't hold on. If you experience chest tightness, tight throat, or difficulty breathing, go to the emergency room immediately. This is because an allergic reaction has affected the respiratory tract. Don't delay.

What many people are most worried about is “Will they never be able to touch this food again in this life?” In fact, it really varies from person to person. Most food allergies in children are caused by the immature immune system. After the age of six or seven, many of them can tolerate it on their own. I once had a little patient who got hives after taking a sip of milk when he was 2 years old. Now he is 7 years old and can drink yogurt every day without any problems. For adults, if you have avoided it for more than half a year without having an attack, you can also try eating a small amount. If there is no reaction, slowly increase the amount. Most people do not need to avoid food for a lifetime. Only a few are particularly serious, such as eating a bite of peanuts and triggering anaphylactic shock, and they need to strictly avoid food for a long time.

To put it bluntly, food allergy dermatitis is not a serious disease, it’s just that the immune system occasionally has a seizure and recognizes the wrong person. Pay more attention to what you eat, especially new foods that you have not tried before. Try to eat two small bites first. If you are really infected, don't panic. You should apply medicine and see a doctor. Don't be afraid to eat this or that every day just because of this. It will make you panic.