What is a food allergy?

Before talking about a food allergy, an allergy must be defined as an excessive reaction of the body to one of the stimuli, and this reaction is absent in healthy people with the same substances. (1).

This reaction causes a variety of allergy-related diseases, such as eczema, asthma and food allergies.

Allergies usually occur as a result of the presence of certain proteins from certain foods, which are responsible for the occurrence of allergic reactions. through the digestive system.

Although the prevalence of the allergy is uncertain, it seems that the prevalence has increased over the past three decades, mainly in countries with a western lifestyle. (2).

And according to a statistical study, the prevalence of allergies reaches 10% in children aged one year. (3)

Studies also indicate that the prevalence of allergies in adults is estimated at 10.8%, with some estimates indicating that the percentage may reach 19%. (4).

Arriving at final data is elusive, due to the large gap in the manifestations of food allergy among sufferers.

Food allergy symptoms

The symptoms that may appear as a result of a food allergy vary, depending on the type of allergy present. as follows:

1- Food allergy caused by IgE antibodies

The symptoms here are more severe than other types, and may also turn into anaphylactic shock. (5).

Symptoms seen include:

• Itching, or tingling in the hair
• The appearance of a rash that is raised from the skin (red in color), and is itchy
• Nausea and vomiting
• dizziness
• Abdominal pain with diarrhea
• to sneeze
• Itching and redness in the eye
• beeps (beeps)

2- Food allergy that is not caused by IgE antibodies

The symptoms are less severe in this type, and may take several days to appear, and often include:

• Redness of the skin and itching, different from the rash seen in the previous pattern. The appearance of the skin is similar to eczema (red, cracked and dry skin) in addition to itching
• Abdominal pain
• vomiting
• diarrhea or constipation
• Loud, unexplained crying (may be the baby’s only symptom)

Food allergy causes

The true cause of allergies is not yet defined, and several factors may combine to make the body sensitize to proteins associated with food.

Which in turn may cause two different types of reaction, as follows:

1- Food allergy caused by IgE antibodies

Food enters the body for the first time without causing any reaction. However, abnormally, immune system cells read it and make immunoglobulins (IgE) against specific proteins within the food-related substance.

When eaten again, the antibodies recognize these proteins, and as a result activate several immune messages.

Activation of these vaccines leads to the release of some inflammatory mediators (histamines) and causes smooth muscle contraction, dilation of blood vessels and secretion of mucus resulting in symptoms of hypersensitivity. (6).

2- food allergy not caused by antibodies (IgE)

Non-IgE-dependent food allergy is a group of disorders in which a subacute or chronic inflammatory response occurs in the gastrointestinal tract.

Unlike the IgE type that causes rapid symptoms and affects multiple organs, the process here occurs slowly. The symptoms are mainly limited to the digestive system.

The causes of this condition are usually water-soluble glycoproteins. Thus, it is able to cross the intestinal mucosa. (7)

Any food-related substance can contain these proteins, but they are most commonly included in the following list:

• the milk
• eggs
• peanuts
• oysters
• wheat
• nuts

Risk factors for food allergy

There may be several factors that make the body ready for an excessive reaction against foods, and some studies and statistics have managed to put a group of important factors, namely:

1- Heredity

Studies point to the role of genetics in the onset of food allergy. Therefore, the presence of a family member with a food allergy will increase the likelihood of allergic reactions in the rest of the family (8).

2- Gender

The difference in the prevalence of food allergy exists between the sexes, and varies according to the age group. In the period before puberty, males are more susceptible to infection, and with the onset of puberty, females become more vulnerable, and the balance returns to equality after menopause (9).

This difference in relationships associated with puberty highlights the role of female hormones in increasing the likelihood of developing a food allergy.

3- The race

Race may be a risk factor for developing a food allergy, and one study found infection rates to be higher in black and Latino people. (10).

4- Atopic dermatitis

Also known as eczema, it is a chronic inflammatory disorder of the skin, whose patients are at high risk of developing food allergies. In addition, asthma and seasonal rhinitis, which are also accompanied by food allergies (11).

5- Hygiene hypothesis

This hypothesis suggests that the less exposed a child is to pathogens growing up, the greater the chance of developing a food allergy. Because this condition causes the immune system to react more severely to food proteins (12).

6- Vitamin D deficiency

Studies have shown that vitamin D deficiency may be a contributing factor to the onset of food allergy (13).

7- Weight gain

The prevalence of food allergy was observed in overweight girls, which supports the idea that weight gain is a catalyst for the appearance of allergies in females and not in males. 2021 academic year.

Complications

Anaphylactic shock is the most important and dangerous complication seen. This occurs in food allergy caused by IgE antibodies.

Anaphylactic shock is a life-threatening medical emergency. Therefore, it requires immediate medical attention. Its symptoms include:

• An imbalance in the blood vessels, which leads to swelling of the tissues under the skin, and the lips, tongue and throat may reach, and suffocation may occur.
• Narrowing of the bronchi leading to breathing difficulties, in addition to the appearance of sounds during breathing (wheezing and stridor).
• persistent cough
• lack of oxygen
• Problems swallowing or speaking
• Dizziness and even fainting
• A severe drop in blood pressure below 90 mm Hg, due to dilation of the blood vessels.

A case of food allergy that is not caused by IgE antibodies may also lead to a group of complications, which appear especially in untreated cases, and in the long term, according to Research of the year 2018 include:

• Malnutrition
• growth failure
• Lack of protein (albumin) in the blood
• in the form

diagnosis

Diagnosing allergies can be a challenge for the doctor, because it is difficult to identify the substance associated with the foods that cause the allergies (13) But in general, the history is very useful in guiding the diagnosis. as follows:

1- Medical history

The doctor asks a number of questions through which he can access useful diagnostic information. Some of the questions include:

• When was the first time you had allergic symptoms?
• How did it appear in the details?
• How long did it take for it to go away?
• With what and how was it treated?
• Does anyone in the family suffer from allergies, or suffer from similar symptoms?

2- Medical tests

There are also a number of tests the doctor may use to confirm the diagnosis, including:

1- Skin prick test

The skin prick test is a common test that aims to diagnose allergies, and it depends on injecting a few drops of the offending substance into the patient’s arm or back, in addition to injecting histamine and saline solution.

The purpose of this method is to estimate the expected degree of swelling based on the swelling at the site of the histamine injection, while noting that the saline solution remains intact supports the diagnosis.

The patient waits for about 15-20 minutes, then the injection sites are carefully checked, and the degree of swelling, if any, is measured.

A positive test does not necessarily mean the presence of an allergy, nor does a negative test categorically rule it out.

2- Blood analysis

Blood tests are useful in the case of food allergy caused by antibodies (IgE), when the doctor takes a sample of the patient’s blood and exposes it to the causative agent.

The percentage of (IgE) present should then be measured, which may be useful in diagnosing the condition.

3- Oral nutrition challenge test

The food challenge is a last option for the doctor, and it is a diet prescribed by the doctor, and it also depends on the introduction of one of the substances related to the foods suspected of causing allergies and its gradual increase.

If any symptoms appear on the patient, the cause has been identified, and if no symptoms appear, then the food-related substance is safe.

This test requires close medical supervision, as the patient may be exposed to anaphylactic shock at any moment. (14)

Food allergy treatment

The treatment of food allergy depends mainly on identifying the causative food and removing it from the diet. It also requires the cooperation of the parents in order to distinguish between these foods, whether by placing labels or by any other means.

The patient and the people accompanying him must undergo good training regarding the symptoms of anaphylactic shock and how to treat and deal with it in an optimal way.

It is also important to keep the patient with an adrenaline injection designed for allergic shock in addition to antihistamines.

Living with a food allergy

The person must live with the symptoms and problems of a food allergy.

Among the most important tips on the subject:

• The most important coping tip is to be able to identify the food allergen, the patient may be able to memorize the list of foods, or clips or labels may help remember the allergen.
• The patient must be fully aware of the degree of food allergy, and if it is severe, he must pay attention to food residues that may be on plates and glasses.
• If a person needs to take out important food items such as milk and cheese. It should be replaced with other substances that achieve the same nutritional benefit.
• Creating or cooking special meals and recipes is an ideal solution, and you only need to search a little in cookbooks, or even invent new meals.
• Ask carefully about the meal ingredients associated with new foods, especially when traveling. Where the patient should read carefully about the cuisine of the countries he wants to visit in order to avoid problems.
• Always carry emergency medicine everywhere, and make sure that family members, friends or any accompanying person, are aware of the steps to be taken in case of anaphylactic shock.

The importance of paying attention to children’s growth must be emphasized, as there can be developmental disorders without the parents noticing. In these cases, a visit to a doctor is the best option.