Food Allergies

Food allergies are classified into 3 groups: IgE-mediated, non-IgE-mediated (simply early and late onset), or combined.

IgE-mediated food allergies

Can cause symptoms that can be severe or fatal. In this type, allergies to milk, egg, wheat and soy that start at an early age may regress with age, while allergies to snacks and fish and shellfish, which start more slowly, often continue into adulthood. Nutrition of regions and societies Common food allergies vary depending on your habits. For example, lentil allergy can be a serious problem in our country.

In sensitive people, it usually occurs with repeated encounters with food. It may manifest itself as urticaria (hives), angioedema, itching in the throat, vomiting, abdominal pain, diarrhea, respiratory distress, wheezing, anaphylaxis (allergic shock) due to the release of some substances, especially histamine, released from the cells responsible for allergy. After the patient takes the food, symptoms begin 10-15 minutes (at most half an hour) and end within 1-2 hours.

The way the food is prepared (pasteurization, boiling, boiling, baking and) may affect the severity of the allergic reaction.

In some cases (such as exercise, presence of infection, alcohol use), more frequent and more severe allergic findings may develop.

Non-IgE-mediated food allergies

Usually skin and affects the gastrointestinal system. It usually presents as atopic dermatitis on the skin. Proctocolitis, which is marked by blood in the stool in young babies (2-3 months), is the most common form. The very small amount of dietary proteins that pass through breast milk is responsible. Rarely, food protein-associated enterocolitis syndrome (FPIES) (vomiting, diarrhea, feeling faint after taking the responsible food, usually in babies older than 7-8 months who are not breastfed), food protein enteropathy (FPE) (constipation, abdominal pain, vomiting, diarrhea in all age groups). , inability to gain weight). Symptoms appear within 2-3 days after ingestion of the responsible food.

Late food allergies generally affect babies and mostly (70%) develop with cow's milk allergy. It is expected to regress between the ages of 1-5. Its frequency is not exactly known due to the lack of diagnostic tests.

Combined food allergies

In this group, both early and late-onset findings occur together. Eosinophilic gastrointestinal diseases such as food allergies associated with atopic dermatitis and allergic eosinophilic esophagitis (allergic esophageal disease) are in this group. It usually begins with non-IgE-mediated late reactions and continues with IgE-mediated allergy.

How is food allergy diagnosed?

First of all, the food It is important that the symptoms develop after taking them and that they usually recur after each food intake. Sometimes there is a symptom and sometimes there is not, the patient should be evaluated for another disease. It should be asked whether there is an allergic disease in the family or the patient himself.

In early-onset allergies, blood tests (food-specific IgE test) and skin tests with the responsible food are useful in detecting the allergenic food. However, in cases of low-level positivity, food challenge tests (feeding food under observation) that can be performed in an experienced allergy center will help in the diagnosis. This evaluation will prevent the separation of patients who are only sensitive but do not develop a real allergic reaction, or patients who are sensitized but immune (have developed tolerance), and prevent patients from dieting in vain. Not every positivity in allergy tests indicates an allergic disease.

In addition, the allergenicity of some foods increases or decreases in different ways of using them. Food form that develops symptoms should be tried. In addition, caution should be exercised if allergic symptoms develop due to food that may contain additives.

The application and evaluation of skin tests and food challenge tests should be performed by experienced pediatric or adult allergists. Interpretation and evaluation of allergic diseases in children and adults may differ.

What does cross-reactivity in foods mean?

There is a cross-reactivity between some nutrients, that is, allergic symptoms may develop with different foods because they carry the same protein particles. Cow's milk, goat's milk and sheep's milk have high cross-reactivity and should not be used interchangeably. Beef and cow's milk may cross-react. Caution should be exercised when eating different nuts, different types of fish, and shellfish due to cross-reactivity. There are also cross-reactions between some pollens and plant nutrients, and oral allergy syndrome (redness and swelling on the lips around the mouth, mouth and mouth) and some fruits and vegetables such as apples, kiwis, melons, and peaches can occur in patients with pollen sensitivity, allergic rhinitis, and respiratory allergic diseases such as asthma. swelling in the throat pain, tingling and itching, etc.) may develop.

How is food allergy treated?

There is no definitive treatment for food allergies yet. Avoidance of the allergic food (elimination/diet treatment) and emergency intervention in allergic reactions constitute the basis of treatment. The food itself and all foods containing small or large amounts of that food protein should be avoided. For example, in case of cow's milk allergy, foods containing small amounts of milk such as milk, canned food, yoghurt, pudding, cheese, butter, etc. and even tarhana should not be eaten. In addition, the presence of milk and its components in ready-made foods should be carefully evaluated and the labels should be read (milk content such as casein, whey, whey). If you are going to eat outside your home (at a restaurant), you should tell the waiter that you have an allergy and be very careful as there may be contamination in the food as many foods can be found side by side.

If symptoms occur after ingesting allergenic foods, adrenaline, antihistamine, cortisone, bronchodilator, serum or even oxygen and shock treatment appropriate to the symptoms should be administered as soon as possible.

In case of anaphylaxis (allergic shock), adrenaline Its treatment corrects symptoms such as urticaria, angioedema, wheezing and hypotension within minutes. Self-administered adrenaline injectors given to patients and their families can be used at home, school, workplace, etc. In case of a reaction in such environments, it should be applied immediately. A second exacerbation may be observed after 4-6 hours in some patients. It is very important to apply adrenaline early to prevent such reactions. Other medications, such as antihistamines (allergy syrups), only treat local symptoms such as urticaria. These treatments are only effective in controlling symptoms and do not correct the underlying disorder. After emergency treatment at home, patients should definitely consult a health institution.

The main treatment for late-developing allergic diseases is to avoid nutrients.

Is vaccination done with nutrients?

Inoculation with nutrients (sensitization to food) is a form of treatment that aims to prevent symptoms by taking the food, similar to the tolerance that can be gained naturally. Food that develops allergenic symptoms It is based on the principle of starting from low amounts and increasing each week. There are successful results for vaccine (oral immunotherapy) application for milk, eggs and peanuts. However, since serious reactions such as anaphylaxis may occur during the application, it is still performed in very specialized centers on a limited number of patients over the age of 3-4 who are not naturally immune. Using methods and drugs that reduce side effects during vaccination increases the success of the treatment. It is a treatment method that can be applied in very few centers in our country. In most patients, at the end of the treatment, the nutrients can be tolerated without any reaction by using the nutrients in small or large amounts continuously (at least 1-2 times a week).

Prognosis

In early infancy, such as cow's milk and eggs A maximum of 50-70% tolerance to food allergies can be achieved after the age of 3-4, and 80-85% tolerance can be achieved after the age of 15-16. However, in a group of 10-15%, it may last a lifetime, especially in patients with IgE-mediated allergies. Tolerance development is more common in non-IgE-mediated food allergies. In a very small number of patients, such allergies may begin in adulthood. However, in late-onset allergies such as wheat, fish and seafood, and nuts, the development of tolerance is very low and an average of 20% should be expected only after many years.

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