Food allergy is responsible for 20% of all unwanted body reactions to foods. Food allergy is actually an overreaction of the immune system to certain foods or food additives. The first time a person eats food, no symptoms are caused, but this first encounter puts the body on alert and when the person consumes the food for the second time, an allergic reaction will occur.
Food allergy can be mediated by IgE antibodies (rapid hypersensitivity within 20 minutes to an hour) or without IgE mediation (delayed response). In most cases, during the first encounter with an allergen, the body’s immune system produces an antibody called immunoglobulin E (IgE).
This IgE binds to the receptors of two types of body cells called mast cells and eosinophils and causes the release of histamine and other chemicals.
These chemicals cause allergic reactions in the body. The allergic reaction may start shortly after eating the food, or there may be hours between eating the food and the onset of symptoms.
Food allergy is associated with significant socio-economic effects. Its maximum prevalence goes back to childhood and its highest incidence is seen in the first year of life, but reports of food allergies by adults are also common.
This disease causes the exclusion of children from school deli stalls and their full participation in school and community activities.
Mothers of children with food allergies may be forced to leave their jobs to take care of their children at home, as many institutions are unwilling and unable to care for these children, ultimately resulting in a significant economic loss to society. enters
Considering current and future public health needs, economic and social consequences, prevention and treatment of allergic reactions to foods is a major challenge to be addressed.
Patients presenting with food-related symptoms should undergo diagnostic tests to find the culprit food and evaluate a wide range of diseases, from atopic dermatitis, frequent vomiting or diarrhea, urticaria and anaphylaxis, to bronchial asthma.
The diagnosis of causal and normal relationship is only possible with a positive oral challenge of that food compared to placebo, and a negative challenge through free eating also rules out food allergies.
These challenges can only be done when cardiovascular resuscitation facilities are available. After proving the food allergy, the person’s food plans and any changes in them should be drawn with the help of the patient or his family.
Prevalence
It is estimated that between 11 and 26 million Europeans suffer from food allergies. If we extrapolate this estimated prevalence to the world’s population of 6,659,040,000, then we will have a prevalence of 220 to 550 million people with allergies worldwide, which will be a heavy burden for global health.
Although we have information on the current trends in the prevalence of asthma, allergic rhinoconjunctivitis and eczema in children from around the world, no study has evaluated the prevalence of food allergies and its changes over time.
The issue is complicated when we know that only a small percentage of those who think they have a food allergy (for example, self-report that a certain food has had a negative effect on their health), actually have an IgE-mediated food allergy. or cell-mediated sensitization.
In the 80s, 30% of women declared that they or someone in their family had a food allergy.
Since the mid-1990s, a comparison has been made between self-reported allergies and those proven by food challenge; The prevalence of 12.4% to 25% of food allergies based on the self-report of people, was confirmed only in 1.5% to 3.5% of cases with food challenge, which indicates to what extent, any type of reaction caused by consuming foods to Falsely attributed to true food allergies. This statistic was confirmed when the prevalence was between 2.3 and 3.6% in the open population study, through challenge; Only a few of those who thought they had a food allergy had a positive skin test with the same food.
Therefore, two separate groups of “Epidemiology of Food Allergies” can be mentioned:
The group who think they have food allergies: This group is not a “true” representative of the epidemiology of food allergies, but it is a sign of the potential need for allergy medicine.
This is of great help to healthcare providers in planning for demand for allergy services, as well as food industry strategies;
The group whose food sensitivity is confirmed based on the challenge: this group represents the true dimensions of the problem clinically.
Food allergies are a major concern in young children, where the rate of food allergy (which is often life-threatening) is higher in toddlers (5-8%) than in adults (1-2%).
Knowledge of the epidemiology of food allergies is vital for preventive planning. Clinical
symptoms
of food allergies include a wide range of IgE-dependent and non-IgE-dependent clinical syndromes.
IgE-related reactions usually occur immediately or within one to two hours after consuming food, while non-IgE-related reactions occur later. These reactions can occur by eating, inhaling or coming in contact with food.
Cutaneous manifestations : food allergy not only leads to immediate reactions such as urticaria and angioedema, but also plays an important pathogenic role in a subgroup of patients, especially children and infants with atopic eczema (AE).
About 40% of infants and young children with moderate to severe AE have food allergies, which in about 90% of cases include allergies to eggs, cow’s milk, soy, and wheat.
| IgE dependent | Mixed (dependent and non-IgE dependent) | Non-IgE dependent |
| angioedema | Eosinophilic gastroenteropathy | Enteropathy with protein excretion |
| Nausea and vomiting | Gastroesophageal reflux | Protein-induced proctocolitis |
| Rhinoconjunctivitis | Protein induced enterocolitis | constipation |
| laryngeal edema | colic | Heiner’s syndrome |
| Systemic anaphylaxis | Pulmonary hemosiderosis | |
| Oral allergy syndrome | urticaria | |
| Itchy mouth and abdominal pain | ||
| diarrhea | ||
| Wheezing, asthma | ||
| Utopian dramatics |
Gastrointestinal Manifestations : Manifestations of IgE-related reactions in the gastrointestinal tract include itching of the lips and mouth, abdominal pain, diarrhea, and vomiting, which occur shortly after consuming food.
In non-IgE-dependent reactions, it is much more difficult to establish a cause and effect relationship with food. Symptoms in food allergy-induced gastroesophageal reflux (GER) are quite similar to those seen in primary gastroesophageal reflux disease (GERD).
Eosinophilic esophagitis refers to eosinophilic inflammation of the esophagus. Foods have been implicated in allergic eosinophilic esophagitis (AEE) and allergic eosinophilic gastroenteritis (AGE). Enterocolitis syndrome caused by food proteins (FPIES), usually manifests with severe vomiting and diarrhea within two to three hours after eating the culprit allergen, and causes dehydration and lethargy in infants who are fed formula.
Allergic proctitis usually occurs up to 6 months in infants who are breastfed or sometimes in those who are fed formula.
Studies have shown the improvement of colic symptoms after removing milk or changing formulas, but the pathological mechanism of the disease is still not clear.
Food allergy has also been suggested as a cause of constipation in children and infants.
Respiratory manifestations : Food allergy may present with a variety of respiratory symptoms, usually involving IgE-dependent responses, such as runny nose and wheezing.
Asthma or chronic or isolated rhinitis due to food allergy is uncommon. Heiner’s syndrome is a type of lung disease caused by food allergy, which is often caused by cow’s milk and mainly affects infants.
In the course of it, milk-specific IgE may be found.
General manifestations : Anaphylaxis is the most severe manifestation of food allergy. This disease, which has recently been given a new definition, with its increasing prevalence, has greatly increased the burden caused by food allergy.
An estimated 30,000 cases of food-induced anaphylaxis occur annually in the United States, resulting in 2,000 hospitalizations and 200 deaths per year.
The basis of treatment for these reactions, which are often unpredictable, is the injection of epinephrine into the thigh muscle.
Also, it is necessary to train school teachers and health personnel in order to ensure the correct use of the epinephrine auto-injector.
Early allergy symptoms in most cases include : wheezing, vomiting, hives, angioedema (accumulation of fluid in body tissues that causes swelling) and itchy lesions on the skin, and delayed allergy symptoms in most cases include: diarrhea, Vomiting, irritability, abdominal pain and growth retardation.
What percentage of children and adults have food allergies?
Food allergies and sensitivities are more common in children than in adults.
Food allergy is seen in 6-8% of children and 1-2% of adults.
The prevalence of food allergies is higher in children with other allergies.
About 35% of children with severe eczema also have food allergies, and 6% of children with asthma experience wheezing caused by food allergies.
What are the risk factors for food allergies?
Although the risk factors have not been fully identified, the role of some factors in the occurrence of allergies has been identified. Heredity plays an important role in the development of allergies, so that if both parents have allergies, the risk of developing allergies in a child is 75%, and if one of the parents is allergic, the risk is 50%.
The most important risk factors after heredity are the lack of exclusive breastfeeding in the first 6 months of life and the early start of complementary feeding (before 6 months of age).
Regarding other effective factors, studies have been conducted with conflicting results; Among these factors, we can mention the consumption of allergenic food by the mother during pregnancy, race, sex of the fetus, age of the mother at the time of pregnancy, cesarean delivery, number of pregnancies of the mother and contact with environmental pollution.
It is also said that dust, pollen of flowers and plants, cigarette smoke, stress, cold or intense exercise after eating food may aggravate the clinical symptoms of food allergy.
What are the symptoms of food allergy?
The type and severity of food allergy symptoms vary from person to person and depending on the type of allergen. The most common signs and symptoms of food allergy are:
Gastrointestinal involvement : itching and burning mouth, nausea, vomiting, bloating, diarrhea, abdominal pain, blood in stools, incontinence, etc.
Skin involvement: hives, itching, eczema, swelling Lips, tongue, face and throat, redness of the skin, swelling and redness around the eyes, etc.
Involvement of the respiratory system : wheezing, hoarseness, shortness of breath, chronic cough, etc.
Involvement of the circulatory system : hypotension, Heart palpitations and heart rhythm changes.
Involvement of the nervous system : dizziness, anxiety, headache, light-headedness, decreased level of consciousness, drowsiness, etc.
Although adverse reactions to any food can occur, eight types of food and their related compounds are responsible for the majority of food allergies. These eight foods are:
cow’s milk, eggs, fish and crustaceans, soybeans, tree nuts, peanuts, wheat, some fruits and vegetables.
The most common age of cow’s milk allergy is in the first 2 years of life. Cow’s milk protein allergy means that the infant’s or child’s body shows an abnormal immune reaction in the form of sensitivity to the proteins in cow’s milk. About 1 to 7.5% of infants are sensitive to proteins in cow’s milk and milk powders made from cow’s milk. Most infants who are allergic to cow’s milk recover by the age of 4 to 6 years. Boiling milk has no effect in eliminating the allergenic property of cow’s milk protein. Because cow’s milk protein is resistant to heat. Some infants show allergy symptoms after consuming breast milk, because breast milk may also contain small amounts of cow’s milk protein in cases where the mother used cow’s milk in her diet.
What sources contain cow’s milk?
In addition to the fact that foods such as butter, cheese, cream, ice cream, yogurt, cream, curd, whey, yogurt and cheese contain cow’s milk, sauce, some chocolates, sweets, cakes and biscuits containing milk, caramel fritters, Margarine, some ready-made soups and puddings may also contain cow’s milk protein. In some cases, in the food industry, substances containing cow’s milk proteins are used and have different names. Patients with cow’s milk allergy should read the food label carefully before consuming these products, which contain cow’s milk proteins. Some of these names that may be seen on the label of prepared foods are:
| casein | Protein hydrolyzate | Potassium caseinate |
| Caseinate | Magnesium caseinate | Sodium caseinate |
| Ammonium caseinate | Lactoalbumin | Whey protein |
| Calcium caseinate | Lactoalbumin phosphate | Hydrolyzed casein |
| Whey powder | Lactoacidophilus | Whey |
| Milk powder | Milk Formula |
Replacing milk in the diet of a child who is allergic to cow’s milk:
If your child is allergic to cow’s milk, using soy milk powder may be the right solution. The nutritional value of soy milk powder and cow’s milk powder is the same.
In some studies, it has been mentioned that 8-15% of infants who are allergic to cow’s milk also react to soy milk powder, in which case low-allergen (hypo-allergenic) milk powders should be used for the child. A nursing mother with a cow’s milk allergy who is breastfeeding her child should eliminate all dairy products from her diet and add calcium, vitamin D and other nutritional supplements to her diet with the doctor’s advice.
Fortunately, cow’s milk is one of the easiest ingredients to replace in cooking a variety of foods. You can use water or natural fruit juice instead of milk. Also, the mother can express her own milk and use it to prepare infant food. Also, milk made from soybeans can be used to prepare baby food.
Egg allergy is often associated with cow’s milk allergy, but it can also occur alone. Most egg allergens are found in egg whites, but egg yolks can also contain allergen proteins. Therefore, if your child is allergic to eggs, he should avoid both egg yolks and egg whites. Patients who are allergic to eggs may develop symptoms a few minutes to a few hours after eating eggs. Symptoms can be skin (red, itchy and swollen rash or dry skin), digestive (nausea, vomiting, diarrhea, abdominal pain), or respiratory (sneezing, coughing, runny nose, triggering asthma attacks).
Egg allergy usually improves by age 5. Allergy to eggs can cause many problems for the patient, because many foods that children eat contain eggs, and in some cases, it is difficult to diagnose the allergy due to the fact that eggs are hidden in food. Parents should eliminate all foods containing eggs from the child’s diet, and should also read food labels carefully and avoid giving any foods containing eggs to the child.
What sources contain eggs?
Foods such as desserts, cakes, pastries, biscuits, some foods containing butter, pasta, mayonnaise, omelets, cookies, pies, souffles, and some soups contain eggs.
Meanwhile, in food labels, you should look for egg products under different headings and you should avoid foods that contain these ingredients:
| Eggs in any form | |||
| (whole eggs, dried eggs; powdered eggs, frozen eggs, beaten eggs or egg whites) | |||
| Albumin | Albumin | globulin | Ovtila |
| Apovitilin | Albuminate | Flavoprotein | Euthelin |
| Vitilin | Oveoglobulin | Ovoglycoprotein | Avidin |
| lutein | ovumocoid | Oomocin | Ovotransferrin |
What ingredients can be used instead of eggs in preparing food?
Are the triple vaccine and the flu vaccine dangerous?
Triple vaccine and influenza vaccine may contain egg protein if prepared in media obtained from egg cells. In various investigations, it has been determined that the triple vaccine is either free of egg allergen or contains very small amounts of eggs, so it is not recommended to do a sensitivity test to the vaccine and it is safe to take the triple vaccine unless the child has already had a reaction. Severely allergic to eggs (anaphylaxis). The flu vaccine contains higher amounts of egg allergen, so all children and adults with egg sensitivities should be tested before getting the flu shot.
It is a common cause of allergies in children and adults. It is said that unlike many food items, peanut allergens are not destroyed by heat and even the allergenicity of peanuts is enhanced by heating. Therefore, roasted peanuts and peanut oil are more allergenic than raw peanuts. If your child is allergic to peanuts, you should prevent him from eating peanuts and all products containing them. (Even foods made with peanut oil should be avoided.) People who are allergic to peanuts are also at risk for allergies to other types of nuts. While the prevalence of nut and peanut allergies is increasing, peanut allergies rarely go away. To avoid peanut allergy, all peanut products should be removed from the child’s diet at least until the age of three.
What sources contain peanuts?
Many salad dressings and dressings, some pastries and puddings, pancakes, and some Asian and Mexican foods contain peanut oil. If the label of ready-to-eat foods mentions plant protein, you should avoid eating them because they may contain peanuts.
Tree nuts include walnuts, hazelnuts, almonds, pistachios and acorns.
Nut allergies can be very severe and, like peanut allergies, are usually lifelong. It is said that 20% of people who are allergic to peanuts also react to tree nuts, and people who are allergic to tree nuts can also be allergic to peanuts.
Therefore, it is recommended that if your child is allergic to one type of nut, he should also avoid other types of nuts. Nut allergy symptoms often begin as a runny nose, skin rash, or burning tongue and can quickly progress to anaphylaxis symptoms.
Some people who are allergic to plant pollen are also allergic to tree nuts.
What sources contain nuts?
Many African, Indian, and Asian foods contain nuts or oils made from nuts, and some cookies, pastries, chocolates, ice creams, and desserts may also contain nuts or nut oils. To know the presence of nuts, you must read the label on the food carefully.
Allergy to fish and crustaceans is a major cause of allergy in adults. Fish allergens are actually proteins found in fish tissue. These allergens are found in most types of fish. However, some people are allergic to only one type of fish.
Allergies to fish and shellfish are often lifelong. Crustaceans such as shrimps, crabs and lobsters and bivalves as well as molluscs cause allergy symptoms in some people. Some patients are allergic to only one species of fish or crustaceans, and some are allergic to several species.
In some studies, it has been shown that some patients are allergic to mites and house dust at the same time as they are allergic to sea shells. Note that sometimes an allergic reaction can occur after inhaling the smell of cooking fish or after touching fish. Even if the food served in seafood restaurants does not contain fish and crustaceans, it may come into contact with fish and crustaceans during the stages of food storage, preparation and cooking, and cause problems for very sensitive people.
Wheat allergy usually occurs in children and often improves with time. In most patients, allergy is seen only to wheat. Wheat allergy is different from celiac disease. Celiac disease is an inappropriate reaction to gluten in grains that is lifelong. Patients with wheat allergy may react to barley and rye in addition to wheat, and these patients should read all food labels carefully because even some ice creams and sauces can contain wheat flour.
What ingredients can be used instead of wheat in cooking?
Other grains such as rice and corn can be used in a wheat-free diet. But some other types of cereals may be dangerous due to allergic interference (barley and rye). Often, in these diets, it is better to use a mixture of flour from several types of grains as a substitute for wheat flour. Instead of one cup of wheat flour, you can use any of the following recipes in preparing food:
5.8 cups of rice flour,
7.8 cups Potato starch flour,
one cup of soy flour with 1/4 cup of potato starch flour,
one cup of corn flour.
Soy is another ingredient that can cause allergies. Although soybeans are not usually used in their intact form in food, products derived from soybeans are used in many ready-to-eat foods that people who are sensitive to soy should avoid consuming soy, soy butter, soy sauce, protein. Avoid soy, soy milk and soy flour. Some research shows that people who are sensitive to soy can use soybean oil. It should be noted that in food labels, terms are sometimes used that mean soy products and should be avoided, these terms are given below:
hydrolyzed vegetable protein
vegetable protein Textured
vegetable starch
vegetable texture
Among fruits, allergies to red apples and peaches are more common, and among vegetables, allergies to celery, parsley, and tomatoes are more common. Meanwhile, in some people, handling and cutting kiwi fruit can also cause symptoms. Allergies to fruits and vegetables are often accompanied by pollen allergies. For example, 50% of people allergic to birch pollen are also allergic to apples.
Most children with food allergies are treated by general practitioners.
Currently, the only treatment available for food allergies is to avoid the food or foods known to be allergenic to the individual.
Care and control of the foods used is the only way that affects the clinical manifestations of food allergies (including delayed sensitivities) and atopic dermatitis. Nevertheless, during the treatment regimen of food allergy sufferers, we will encounter problems in practice that should be taken into consideration in outpatient consultations at the individual level:
What is a cross reaction?
Allergies are usually seen to several types of food. If your child is allergic to one substance, it is likely that he will be allergic to other substances as well.
Each food item belongs to a food family. The food items in the food family have some features in common, including the allergenic feature. If the child reacts to a food item, it should be checked for allergies to other foods in that food family.
For example, the peach fruit belongs to the cherry family. There are various fruits in the cherry family, such as peaches, plums, apricots, cherries, nectarines, and almonds, and if the child is allergic to peaches, other fruits should also be tested for causing allergies in the child. This reaction is called cross reaction.
Another type of cross-reaction is between food allergens and inhaled allergens (such as house dust, pollen from flowers and plants). For example, a child who is allergic to birch pollen may show similar symptoms by eating apples, carrots, celery, peaches, plums, pears, cherries, hazelnuts, and raw potatoes.
Expert diagnosis, treatment for allergies, asthma, eczema, and more by Dr. Hedayat Akbari, a renowned allergist with 30+ years of experience.
