Food allergy: diagnosis, difference from intolerance and treatment in Tashkent

Allergies and intolerances: what's the difference?

This is the most important fork in the road, and confusion here costs people unnecessary restrictions, and sometimes even health. In case of allergies, the immune system is to blame: it produces antibodies to food protein, and the reaction is triggered by contact with it. With intolerance, the immune system is not involved - the body simply cannot digest or absorb the food component normally.

• Mechanism: allergy - immune reaction to protein; intolerance - lack of an enzyme, a reaction to a chemical in a product, or a bowel habit
• Dose: in case of allergies, even trace amounts cause a reaction; in case of intolerance, a person usually tolerates a small portion normally
• Time: allergies develop in minutes to two hours; intolerance appears later, usually after a few hours, and depends on the amount eaten
• Manifestations: for allergies - skin, breathing, swelling, drop in pressure; with intolerance - almost always only the stomach: bloating, rumbling, pain, loose stool
• Danger: allergies can lead to anaphylaxis; intolerance is unpleasant, but not life threatening
• Tactics: in case of allergies, exclude the product completely; in case of intolerance, select a tolerable portion or enzyme preparations

The most telling example is milk. Lactose intolerance means a lack of the enzyme lactase, which breaks down milk sugar. It manifests itself as bloating, rumbling and loose stools an hour or two after a glass of milk, while fermented milk products and hard cheese, which contain little lactose, are tolerated normally, and a glass of kefir does not cause any problems. An allergy to cow's milk protein is quite different: it can occur to any amount and any dairy product, including cheese, and manifests itself as a rash, vomiting, and in infants, blood in the stool and poor weight gain. The first occurs in adults very often and is not a disease in the full sense of the word, the second is typical for young children and requires a real exception.

What products and at what age

Although any food can theoretically cause a reaction, in practice the vast majority of cases occur in a limited list, and it differs markedly between children and adults.

• In young children: cow's milk, chicken egg, wheat, soy. Most of these allergies go away over time
• For older children and adults: peanuts, nuts, fish, seafood, sesame. These reactions often persist for life and are often severe
• Cross-reactions with pollen: in people with hay fever - fresh fruits, vegetables, nuts, melons. Usually limited to itching in the mouth
• Hidden sources: milk protein in sausages and baked goods, peanuts in sauces and sweets, breaded eggs and mayonnaise, sesame seeds in bread and halva, fish protein in bouillon cubes
• A separate form is anaphylaxis caused by physical exertion after eating: the reaction occurs only if the consumption of a product, usually wheat, is followed by exercise; the product itself is tolerated alone

Another thing parents should be aware of is that recommendations for introducing complementary foods have changed in recent years. Previously, the advice was to put off potentially allergenic foods for as long as possible. Today, the evidence suggests the opposite: the timely introduction of foods such as eggs and peanuts in age-appropriate forms at normal complementary feeding times reduces the risk of developing allergies rather than increases them. Delaying acquaintance does not protect. In a child with severe atopic dermatitis or an already established allergy, the administration procedure is discussed with the doctor separately.

What does it look like and how quickly does it develop?

According to the time and mechanism of reactions, they are divided into two large groups, and both diagnosis and danger depend on this.

1. Немедленные реакции — от нескольких минут до двух часов. Именно они опасны: крапивница, отёк губ и век, рвота, спазмы в животе, свистящее дыхание, падение давления. Такие реакции хорошо выявляются кожными пробами и анализом на специфические IgE.
2. Отсроченные реакции — от нескольких часов до суток и дольше. Сюда относят обострение атопического дерматита, некоторые виды поражения кишечника у грудных детей, кровь в стуле. Аллергопробы при них часто неинформативны, и основным инструментом становится пробное исключение продукта с последующим возвращением.
3. Оральный аллергический синдром — зуд и покалывание во рту от свежих фруктов и овощей у людей с поллинозом. Обычно проходит за минуты и ограничивается полостью рта.
4. Синдром, вызванный пищевыми белками, у младенцев: обильная повторная рвота через 1–4 часа после кормления, бледность, вялость, иногда обезвоживание. Сыпи при этом может не быть вовсе, что затрудняет распознавание.

The severity of the previous reaction does not guarantee the severity of the next one - this is one of the most important practical conclusions. A person who previously only had hives may get anaphylaxis the next time they are exposed, and vice versa. Therefore, if there is a confirmed allergy to foods with a high risk of severe reactions, the doctor will draw up a written action plan, and not limit itself to the advice “just don’t eat it.”

Diagnostics: what works and what is a waste of money

Examination for food allergies is structured around the clinical picture. No analysis by itself makes a diagnosis: it confirms or refutes a specific suspicion arising from the medical history.

1. Пищевой дневник: что съедено, в каком количестве, через сколько времени и что именно произошло. Это скучно, но нередко даёт больше, чем панель анализов.
2. Кожные прик-тесты с подозреваемыми продуктами — быстро, наглядно, результат через 15–20 минут.
3. Специфические IgE в крови к конкретным продуктам, а не к сотне сразу. Уровень антител отчасти коррелирует с вероятностью реакции, и его отслеживают в динамике у детей.
4. Молекулярная диагностика по отдельным белкам — помогает понять, грозит ли человеку тяжёлая системная реакция или дело ограничится зудом во рту.
5. Диагностическое исключение продукта на 2–4 недели с оценкой динамики симптомов, а затем контролируемое возвращение.
6. Провокационная проба под наблюдением врача — самый достоверный метод. Проводится только в условиях, где готовы оказать помощь при реакции, и никогда не делается дома.

Now about what not to do. Testing for IgG and IgG4 antibodies to food products is the most common and most expensive mistake. These antibodies are produced in response to normal food contact and are found in healthy people: essentially, they reflect what a person eats, not what they are allergic to. Allergology societies do not specifically recommend using these tests to diagnose food allergies or “intolerances.” The result usually comes in the form of a long list of “forbidden” foods, which leads to a diet that is not justified in any way. Bioresonance diagnostics, hair testing, kinesiological tests and “analysis of 100 products with a drop of blood” are equally baseless.

Treatment and life with diagnosis

There is no medicine that reverses food allergies. The basis is the exclusion of the product and preparedness for a reaction in case of accidental exposure. And “eliminate” means not only not eating the obvious dish, but also dealing with hidden sources and cross-contamination in the kitchen.

• Read the ingredients every time, including familiar products: recipes change without notice
• Know the synonyms: casein and whey are milk, animal albumin and lecithin are eggs, and “vegetable protein” can be soy.
• In cafes and at a party, name the allergen directly, and do not ask “are there any nuts here”; check whether they were cooked on the same surface
• At home, if you have severe allergies, use a separate cutting board and utensils, thoroughly wash surfaces: traces on a shared frying pan are often enough
• Have a written plan of action in case of a reaction and medications prescribed by a doctor with you, and not in your home medicine cabinet
• Inform the school or kindergarten in writing: the teacher must know not only what is not allowed, but also what to do
• Carry information about your allergies with you - in the form of a bracelet, card or note in a visible place on your phone

Children change a lot over time, and this is the most encouraging part of the topic. Allergies to cow's milk protein and chicken eggs go away in most children by school age, and allergies to wheat and soy are also common. Allergies to peanuts, nuts, fish and seafood last longer and often last a lifetime. This is why children with food allergies need monitoring: the doctor periodically repeats the tests and decides when it is safe to try returning the product. A lifelong “just in case” diet, without re-evaluation, deprives the child of adequate nutrition where the allergy has already passed.