Allergology has evolved over 100 years since the term allergic reaction (Allergie) was coined by the Orly pediatrician Pirquet in 1906. The World Allergic Organization (WAO) has conducted epidemiological surveys of allergic diseases in 30 countries, showing that among the 1.2 billion people surveyed, about 22% suffered from IgE-mediated allergic diseases; with the change of modern lifestyle, more and more allergens may cause allergies. This all suggests the multiplicity and frequent occurrence of allergic diseases. For the common gastrointestinal conditions such as regurgitation, vomiting, mucus stools with blood, anorexia, dyspareunia, sudden vomiting and diarrhea with shock-like manifestations in infants and children, if the empirical treatment is ineffective, the condition is recurrent, the histopathology has characteristic manifestations, and the symptoms disappear after avoiding the corresponding allergenic foods, it is suggested that the symptoms are caused by food allergy. The related diagnostic names are allergic eosinophilic gastroenteritis (AEGE), food protein-induced small bowel colitis syndrome (FPIES), allergic proctocolitis (AP), and allergic gastrointestinal motility disorder (AGMD). Among them, AP is by far the most common food allergy diarrhea in infancy, with a mean age of onset of 3 months, exclusive or mixed breastfeeding, sudden onset, non-severe diarrhea, mucus and blood in stool, leukocytes, erythrocytes or occult blood (+) on stool microscopy, generally not affecting feeding, no developmental delay or anemia, focal mucosal erythema, brittle, small nodules, eosinophilic infiltration of the lamina propria on colon microscopy, and often with Family history of allergic diseases. Symptoms are prolonged despite long-term antibiotic therapy. AEGE manifests as mucosal, muscular and plasma membrane inflammation of the intestine; FPIES as recurrent acute vomiting and diarrhea, infection shock-like manifestations, but lacking the basis of the infectious agent; AGMD mainly manifests as abnormal gastrointestinal dynamics, but anti-reflux and relief of constipation treatment is ineffective. At present, domestic and foreign authoritative organizations believe that the diagnosis can be made based on clinical manifestations, corresponding auxiliary examinations, histopathology of the diseased intestine, and double-blind placebo-controlled food excitation. Most of the above conditions develop during lactation, and management is mainly based on avoidance of high-risk foods by the lactating mother and the use of deeply hydrolyzed milk protein formulas or amino acid formulas for artificially fed children. Skin tests showed strong positive skin tests for red meat (pork, beef, lamb) and positive IgE for pork and beef. During the 1-year follow-up, the patient had a recurrence of generalized urticaria, dyspnea, and hypotensive shock after inadvertent ingestion of a small amount of pork. After the patient was instructed to follow a strict diet, the patient had no further episodes of allergic reactions. Foggs, president of the American College of Allergy, Asthma and Immunology (ACAAI), has classified adverse food reactions into food allergies and food intolerances (see the table at right for details of the types included in both), depending on whether they are mediated by immune mechanisms. The guidelines recommend considering the presence of food allergy in the following groups: ① Severe allergic reactions within minutes of ingesting a food, especially in young children; allergic symptoms after repeated ingestion of a specific food. ② Infants and children diagnosed with moderate or severe atopic dermatitis (AD), eosinophilic esophagitis (EoE), small bowel colitis, enteropathy, or AP. (iii) Adults with EoE. However, studies have shown that 50% to 90% of people who report themselves as “food allergic” are not allergic reactions. Guidelines recommend the use of skin prick testing (SPT) and serum sIgE testing to help identify those suspected food allergens, but SPT and serum sIgE testing alone cannot diagnose IgE-mediated food allergy. For non-IgE-mediated food allergy (e.g., FPIES, AP) and mixed food-induced allergic disorders (e.g., EoE), a meaningful relevant history, and remission of symptoms after exclusion of the suspected food, can be the basis for the diagnosis of food allergy. The guidelines recommend the use of oral food provocation tests for the diagnosis of food allergy. For patients with a supportive history and laboratory tests, a positive provocation can diagnose food allergy. A positive oral provocation test can be judged by whether the oral provocation test turns negative when the patient’s symptoms have resolved and it is considered possible to stop the exclusion diet regarding the allergic food. The guidelines state that for eosinophil histamine release/activation tests, allergen-specific IgG, and electrical skin tests, they should not be used for the evaluation of food allergy because there is no evidence that these tests are valuable in diagnosing food allergy. Management of food allergy Patients diagnosed with food allergy should avoid the specific allergen in question and have a physician determine whether certain cross-reactive foods should also be avoided. In patients who also have atopic dermatitis, bronchial asthma, or eosinophilic esophagitis, avoidance of foods to which the allergy is confirmed may alleviate the co-morbidities. However, in patients who are not sensitized or in whom the suspected food is not clinically relevant, avoidance of the suspected allergic food not only does not alleviate the condition, but also poses a risk of nutritional deficiency and growth retardation. There are no medications available to prevent the development of allergic food-induced allergic reactions, and allergen-specific immunotherapy is not recommended for the treatment of IgE-type food allergy. The guidelines do not recommend dietary restrictions for mothers during pregnancy and lactation in order to stop the progression or clinical course of food allergy. All infants and children should be exclusively breastfed for 4 to 6 months, except in special circumstances. For at-risk infants who are not breastfed exclusively, the use of infant hydrolyzed formula rather than cow’s milk formula may prevent the development of food allergy. In terms of preventing death or major complications, epinephrine is emphasized as the first-line treatment for all cases of severe allergic reactions. The use of antihistamines instead of epinephrine has been reported to have the potential to cause death or worsen complications. In addition, for vaccination of food allergy patients, the guidelines state that children with a history of severe allergic reactions should be evaluated for relevant allergic reactions and vaccine allergy testing.