What Are the Signs of an Allergic Reaction to Soy?

Food allergy is also known as allergic reaction of digestive system or allergic gastroenteritis, food allergy, etc., and is caused by certain foods or food additives, such as IgE-mediated and non-IgE Mediated immune response leading to allergic reactions in the digestive system or systemically.

The incidence of food allergies has increased year by year, which has seriously affected people's health and quality of life. Traditional Chinese medicine has a good theoretical and clinical basis for treating food allergies. Therefore, exploring the etiology and pathogenesis of TCM in food allergies will further improve TCM treatment. The efficacy of food allergies is of great significance. There is a great correlation between food allergy and "wind evil" pathogenicity, and allergic constitution is the root cause of food allergy. The important causes of allergic constitution are lack of lung health, weak spleen and stomach, and insufficient kidney qi. ^[1]

FA refers to adverse food reactions mediated by immune mechanisms. A food-mediated non-immune response is called food intolerance. FAs can be further divided into IgE-mediated, non-IgE-mediated FAs, and hybrid FAs that are co-mediated by IgE and non-IgE. IgE-mediated FA is a type 1 allergy with a clear pathogenesis. In infants and young children, due to the imperfect gastrointestinal immune function and mucosal barrier function, high permeability, food allergens enter the intestine and are processed by antigen-presenting cells to bind with MHC- molecules and present to T lymphocytes If Th1 / Th2 balance is broken or cannot be formed, FA will be issued. Typical Th1, cytokines include: interleukin (IL) -2, interferon (IFN) -, and tumor necrosis factor (TNF) -; Th2 cytokines include: IL- 4, -5, -10 and -13 etc. When Th1 type response weakens, Th1 / Th2 imbalance, Th2 cells are stimulated by allergens to activate and secrete cytokines such as IL-4, -13, induce allergen-specific B cells to proliferate and differentiate into plasma cells, and produce specific IgE antibodies. The Fc segment of the antibody binds to the IgE receptor on the surface of mast cells or basophils to complete the FA process ^[2]

The severity of clinical manifestations is related to the allergenicity of food and the susceptibility of the host.

1. The clinical symptoms of IgE-mediated food allergies appear quickly, which can be from a few minutes to 1 to 2 hours after eating. Sometimes very small amounts can cause very severe allergic symptoms. In terms of the sequence of symptoms, the earliest symptoms often appear skin and mucosal symptoms. Respiratory symptoms such as asthma appear late or do not appear, but severe cases are often accompanied by respiratory symptoms. Food-induced asthma is more common in infants. Except for those caused by inhalation, other allergic symptoms are generally combined. Although food for older children and adults can induce a variety of allergic symptoms, including shock, it is rare to induce asthma. Food generally does not cause allergic rhinitis, and as the only symptom of food allergies, it is very rare.

Allergic eosinophilic gastrointestinal disease: It is characterized by EOS infiltration in the stomach or small intestine wall, often with increased peripheral blood EOS. EOS infiltrates the mucosa, myometrium, and / or serosa of the stomach or small intestine. Patients often show nausea and vomiting after meals, abdominal pain, intermittent diarrhea, and growth retardation in young infants. Muscle infiltration causes thickening and stiffness of the stomach and small intestine, and clinical signs of obstruction may appear. Subserosial infiltration generally manifests as EOS-induced ascites. The pathogenesis of the disease is unknown. Some of these patients have worsened symptoms after eating a certain food, involving type allergies. Patients with elevated IgE in duodenal fluid and serum are associated with atopic diseases. Positive skin prick tests for multiple foods and inhalants can continue. Iron deficiency anemia and hypoalbuminemia. The disease often affects infants from 6 to 18 months. Diagnosis is based on gastrointestinal biopsy. Patients with a characteristic increase in EOS often have atopic symptoms. Total serum IgE is increased. Various allergen skin tests and RAST, positive reactions, increased peripheral blood EOS, anemia, and other allergic foods. It will take 12 weeks for the symptoms to disappear and the bowel tissue to return to normal.

Intestinal colic in infants: manifested as paroxysmal irritability in infants, crying in extreme pain, leg curl, abdominal distension, venting ^[2]

The most common manifestations of parenteral symptoms are angioedema and various rashes,

1. Avoid allergens Once you have determined that allergens should be strictly avoided from eating again, this is the most effective control method. However, "avoid" should be targeted. For example, the most allergic part of eggs is egg white, and the edible egg yolk part generally loses children's sensitivity to most food antigens after 6-12 months. In addition, most food antigens are not changed by cooking or heating Allergenicity

2. Drugs generally do not advocate long-term prevention with ketotifen and corticosteroids. The effect of oral cromoglycate is uncertain. Nor does it advocate food for IT. But OAS can use allergenic pollen for IT, and after 1 year, most patients have reduced sensitivity to pollen and plant foods. But when the food induces symptoms, it should be treated symptomatically.

Generally, the prognosis is good, and it gradually eases with age. However, improper handling, migration and development of the disease often lead to malnutrition and growth disorders.

Children who are at high risk of atopic disease (referring to one or both parents suffering from atopic disease), especially breastfeeding are encouraged in the first 3 to 6 months after birth. It should also be remembered that many infants with food allergies later develop other atopic diseases. Therefore, in the case of babies with a family history of allergies, doctors should inform their parents of this possibility and advise them not to smoke and keep indoors clean and hygienic.

1. Non-specific laboratory tests revealed no abnormalities in blood biochemistry and three routine tests. A few peripheral blood had mildly increased eosinophils, low pigment anemia, fecal occult blood test, and Charat-Leyden crystals were positive. Total serum IgE increased. Gastrointestinal endoscopy can be normal or non-specific gastrointestinal bleeding and edema. These should not be used as a basis for the diagnosis of food allergies.

2. Specificity check

(1) Skin test of food antigen: According to the combination of the antigen and the corresponding IgE bound on the surface of mast cells, it stimulates the degranulation of mast cells and causes the corresponding clinical manifestations. The main method can provide skin test results of various foods in 15-20min. The following points should be noted before implementing this test:

The amount of food to be stimulated should be strictly controlled.

Suspicious food should be fasted 2 weeks before the challenge.

The antiallergic drugs were stopped 1 week before the challenge, and other treatments were maintained at the lowest level.

Use standard score method for judgment.

The skin prick test occasionally has the risk of inducing a systemic allergic reaction, and it should be carried out with the rescue equipment.

Children over 3 years of age have a negative skin test, which generally excludes the food allergy. A positive result usually indicates that the food is allergic, but there are also some false positives. Children under 3 years of age have a difficult skin test and are more likely to have false negatives.

(2) Elimination of diet: The patient first eats a normal or basic diet within 1 to 2 weeks. The purpose is to clear the original food in the digestive tract, so that all symptoms of food allergies disappear. Then enter the food challenge period, add a food every 2 to 3 days until the symptoms are triggered. The test can be repeated once for the food that is positive for the challenge test to clearly sensitize the food. A positive food exclusion method can only indicate food allergies and cannot be completely confirmed. Because other food abnormal reactions cannot be ruled out, other tests should be comprehensively judged. This test is time-consuming and cumbersome, but does not require special equipment and test conditions, and is suitable for outpatients.

(3) Radio allergosorbent test (RAST): It uses known food antigens to detect the presence or absence of corresponding IgE antibodies in the serum of patients. This method has high accuracy, low false positive rate, and is not affected by patient medication, but it is expensive and cannot detect multiple antigens at the same time.

(4) The double-blind placebo controlled food challenge (DBPCFC): also known as the food provocative test, is a standard indicator for diagnosing a particular food to cause allergies. Patients should strictly avoid touching and eating the tested food and suspected allergic foods one week before and during the food challenge test. In the challenge test, a small dose of a suspected allergic food (or a placebo) was taken orally, and the dose was doubled every 30 to 60 minutes.

Observe the following indicators:

Nausea, vomiting, diarrhea, abdominal pain and other gastrointestinal and parenteral symptoms.

Before the test and within 6-8 hours after the test, the neutrophils in peripheral blood increased by more than 3.5 × 109 / L.

Positive blood test or fecal occult blood test.

There are white blood cells in the stool mucus.

After Hansel staining, there are Charact-Leyden crystals formed by eosinophil debris in the stool.

Three of the above indicators can be confirmed, and two persistent positives are suspected, and further observation is needed. If no symptoms are triggered, the total amount of food has been increased to 8g (dry weight) or the usual amount of food, which can rule out allergic reactions. Delayed response can be further tested with normal food amounts.

1. Radiographic X-ray examination has special important value, including chest fluoroscopy, radiography, gastrointestinal radiography, etc., and has important diagnostic significance for some allergic diseases. In addition, X-ray examination can help identify other non-allergic diseases and rule out complications. Modern imaging diagnosis includes: B-ultrasound, CT, magnetic resonance, and so on. It is also used in the auxiliary diagnosis of allergic diseases when necessary.

2. Drug diagnosis For certain allergic diseases, in the case that can not be confirmed after various tests, some drugs that have a good effect on allergies can also be used, such as epinephrine, 2 receptor stimulants, various anti-tissues Amine drugs, various adrenal corticosteroids, etc., for tentative treatment. If the effect of the drug is outstanding, the diagnosis of allergic disease can be cited from the side. However, in the diagnosis of such tentative drugs, the condition must be comprehensively considered, and the contraindications and possible side effects of the tested drugs on patients must be ruled out.