If a person has hypersensitivity to certain foods against the background of food intolerance symptoms, then this is a food allergy. It is caused by a specific reaction to them from the immune system. At the same time, the mechanisms of such intolerance are individual. Their variety is so vast that it is often difficult to determine the true cause of allergies. Yes, and there are reactions that have a genuine allergic nature, less often than we used to believe.
Types of food allergies
People suffering from diseases of the digestive system (especially dysbacteriosis and peptic ulcer) are more likely to suffer from the action of allergens. This is due to a partial loss of the ability to digest allergen proteins. For the first time, such an allergy is mainly manifested in childhood. Among the reactions associated with intolerance to various foods, the following types are distinguished:
- Reactions of a toxic nature
The reason for their development is the presence of toxic substances in food. Their manifestations may vary depending on the chemical properties that are characteristic of harmful substances in their composition. The severity of the allergy also depends on this indicator. The product itself does not affect how the body reacts. - Reactions of a non-toxic nature
In this group, two more subspecies are distinguished depending on the mechanism of development:
- Reactions of the body to foods associated with disorders in the immune system (this is, in fact, a food allergy);
- Reactions that are not immunological in nature (food intolerance to products).
Cases of food intolerance are combined with diseases of the digestive, endocrine, biliary systems, congenital or acquired fermentopathy, and other problems that are not related to the state of the immune system. Allergization does not develop if the digestive and biliary function is performed in full, without violations.
Causes of food allergies
The disease can be detected both in childhood and much later, in the period of maturity. At the same time, an important point is to determine the cause of the allergy, since only by eliminating provocative factors can a good result in treatment be achieved. At different ages, the causes can differ significantly, so we suggest considering them depending on the age category of patients.
Development of food allergies in children
Even the abuse of the mother of the child during pregnancy by certain products can provoke an allergy in the crumbs. It is also dangerous not to follow a hypoallergenic diet while breastfeeding. You should not eat a lot of nuts, eggs, milk, fish, chocolate and other "dangerous" foods. Also causative factors include:
- Stopping breastfeeding too early, transferring the baby to formula feeding;
- Violation in the formulation of the diet, when the volume of food products and the ratio of ingredients in dishes does not correspond to the age of the child, his weight indicators;
- Pathologies, diseases of the gastrointestinal tract;
- Problems with the liver, bile ducts.
In the full process of digestion, food products should be broken down into compounds that do not have allergic properties. The intestinal wall normally remains impermeable to undigested products. Digestion and then absorption of products depends on the state of the endocrine system, the composition and volume of digestive juices, the usefulness and stability of the intestinal microflora, and local immunity. These processes are influenced by the characteristics of lymphoid tissue and secretory immunoglobulins, as well as a number of other factors.
Causes of Allergies in Adult Patients
In most cases, people learn about the presence of an allergic disease in childhood. But for a number of reasons, it may first appear in adult patients. It contributes to:
- Increased permeability of the intestinal walls, which accompanies inflammatory processes in the gastrointestinal tract;
- Violation of the absorption of food compounds (this can be both an acceleration and a slowdown of the process), which is often caused by a lack of enzymes, weak functionality of the pancreas, biliary dyskinesia or intestines;
- Abnormal acidity of the stomach.
A true allergic reaction to any food is based on hypersensitivity and immune response to repeated exposure to the food allergen. The fact is that at the first intake of a food product, food antigens appear in the bloodstream, and in response to them, the human body synthesizes antibodies of the immunoglobulin class. This process should normally ensure that the immune system is "indifferent" to the product upon subsequent contact with it. This process is under the control of genetics.
Symptoms
The manifestations of food allergies are very diverse. They directly depend not only on the individual characteristics of the organism, but also on the form, severity and localization of the reaction. The development of an allergic syndrome in a patient can be considered the primary and earliest symptom. It refers to a true food allergy. It is characterized by:
- Itching in the mouth;
- Numbness of the tongue;
- Distension of the tongue and palate;
- Swelling of the mucous membrane.
In addition to such local manifestations, there are also several symptoms of food allergy from the digestive system:
- Colic;
- Vomit;
- constipation or diarrhea;
- Loss of appetite;
- Allergic enterocolitis.
Vomiting begins, accompanying an allergy, it can manifest itself both a few minutes after eating, and after 4-6 hours. In most cases, vomit consists of food eaten the day before. This symptom may be persistent. Its development is associated with a reduction in the pylorus when a food allergen enters the stomach. Also fluctuate in time and the manifestation of colic in the abdomen. They are caused by spasm of smooth intestinal muscles. Pain with food allergies can be moderate, but accompany the patient constantly. At the same time, appetite decreases, mucus appears in the stool, and other disorders develop.
Constipation develops against the background of spasm of smooth muscles in the intestine (in its different parts). But frequent stools, which manifests itself as a reaction to the intake of an allergen food product, is one of the most common symptoms in patients of all ages. Diarrhea almost always accompanies an allergy to dairy products. Vitreous mucus is present in the feces. At the same time, flatulence, enterocolitis of an allergic nature may occur. Dizziness, severe weakness, headaches may accompany the reaction.
Allergic dermatoses at any age are the most common in food allergies. Most often they appear in the following forms:
- Hives;
- Atomic dermatitis;
- Quincke's edema.
Sometimes there is also allergic rhinitis. This is a mucous-watery discharge from the nose, accompanied by nasal congestion, difficulty breathing.
Allergy symptoms in babies
If older children and adults have their own range of allergic manifestations, then in infants the disease manifests itself differently:
- Diaper rash of a persistent nature, even with careful skin care;
- Dermatic manifestations in the anus and itching after feeding (this symptom occurs after feeding the crumbs).
As for the localization of skin changes, they have a lot of options. At first, as a rule, they can be seen first on the face, then throughout the body. A clear pattern is revealed between skin exacerbations and the very intake of a food allergen. If there is no treatment, then allergic changes on the skin become permanent, characterized by a relapsing course. This can make it difficult to determine the cause of the allergy.
Diagnostics
A visit to an allergist is mandatory for any manifestations of the disease. He makes a diagnosis based on the examination and complaints of the patient, confirming it with the results of specific studies. Allergic examinations are characterized by the use of food allergens. It is necessary to differentiate food allergies from symptoms of diseases of the gastrointestinal tract, mental disorders, acquired fermentopathy, and helminthic invasion. These conditions may have similar symptoms.
The most accessible test is the cytology of smears from the mucous membranes. It allows you to accurately identify the nature of the reaction (it can be infectious, allergic). Also, skin tests must be included in the examination plan. But the tests of a provocative nature are considered the most reliable. Alas, they can cause a severe reaction on the part of the body, so they are carried out only in a hospital under strict supervision. At the same time, in the hospital department where such a study is carried out, there should be an intensive care unit.
In order to conduct such a provocative test, you need to prepare the patient. Two weeks before his expected date, a strict diet is prescribed that excludes the consumption of the alleged allergen in food. It is carried out on an empty stomach if the patient feels well. Food allergens during the study can be lyophilized or dry products (flour, egg powder, milk powder, meat). The allergen, enclosed in a gelatin capsule, is given to the patient, observing the next day for his condition. Both objective and subjective factors are recorded.
In cases where there is no reaction to the allergen, its dose is increased (from 8 to 20 mg), introducing a new portion of the allergen in a day. With a negative reaction, continue daily increase in dose until the dose reaches 8000 mg (this is 100 g of food). If even after the introduction of 8000 mg there is no reaction to this product, then the testing is stopped. The test product is not considered to be an allergen to the patient.
The following methods are considered the most informative in terms of allergy research:
- Linked immunosorbent assay;
- Radioallergosorbent test;
- Test using modern CAP, MAST-CLA systems.
Treatment of food allergies
Therapy of allergic diseases is based on the following principles:
- A complex approach;
- Accurate adherence to the course stages;
- Parallel elimination of signs of illness and prevention of exacerbations;
- Building an adequate diet (in accordance with the age, weight of the patient, the presence of concomitant diseases).
Specific and non-specific methods are used. The latter are aimed at eliminating symptoms and preventing possible exacerbations. Acute common manifestations of food allergies are a reason to use allergy pills. Antihistamine drugs of the first generation will help - Suprastin or Tavegil.
But if the symptoms are of mild or moderate severity, then new generation antihistamines are taken as the basis for treatment, including:
- Ebastine;
- fexofenadine;
- cetirizine;
- Loratadine.
The main specific method of treatment is the exclusion from the diet of the allergen itself, as well as allergen-specific immunotherapy (or ASIT). Sometimes the absence of rare products in the menu is the only effective method of treatment. But ASIT is used only when the allergen product is vital for development, growth and full functioning (this includes milk in the diet of children).
