Food allergy


At a Food allergy suffers more than one in twenty children in Germany. In such an allergy, the immune system of the body reacts to components of the food that are actually harmless. In adulthood, food allergies are less common. A food allergy must be distinguished from a food intolerance and a pseudoallergy. People with severe food allergy usually need to avoid the food for life. Here you read all important information about food allergy.

Article summary Food allergy

  • description
  • symptoms
  • Causes and risk factors
  • Examinations and diagnosis
  • treatment
  • Disease course and prognosis

Food allergy: description

In allergies, the immune system usually responds to harmless proteins. In doing so, the body erroneously classifies substances from the environment as dangerous that will not harm the body. Food allergies are rarer than many other forms of allergy. About 6.4 percent of adult women and 2.9 percent of men are affected.

Certain foods cause more food allergies than others. These include nuts, shellfish, soybeans, chicken eggs and milk.

Why it comes to such a defense reaction, is not clear. In addition to environmental factors, hereditary components also play a role. Infants are particularly susceptible to food allergy because their gut wall is not as reliable as an adult. For this reason, food components and cells of the immune system are more likely to come into contact with them. A proper diet - depending on the age of the child - is therefore important.

Food allergy also occurs in rare cases in infants who are fully breastfed. Through the mother's diet certain ingredients also get into breast milk, to which the child can react. In general, however, children who are breast-fed have a lower risk of developing allergy.

People who are particularly susceptible to allergic-type diseases are also called atopics. For them, food allergy is only a partial aspect of a lifelong medical history. A food allergy then often occurs early in childhood. It is followed by diseases such as atopic dermatitis, asthma and hay fever, which are also based on an overreaction of the immune system. While food allergy is more likely to affect children, hay fever usually only occurs in adolescence or adulthood.

Food allergy often occurs in combination with certain other allergies. One then speaks of cross-allergies. For example, children who have developed a food allergy to apples usually also respond to birch pollen. If a food allergy is known through a food allergy test, one should also test for known cross allergy. This is achieved by a more detailed allergy test. Food and other environmental pollutants, such as pollen, which the patient should avoid, can be detected in this way.

Food allergy and food intolerance

Many people mix the terms food allergy and food intolerance in everyday life - these are two different diseases. In contrast to allergies, incompatibility does not lead to any reaction of the immune system, nor are the triggering substances recognized by antibodies of the IgE type. Incompatibilities are rather disrupted physical processes, so that a food either can not be properly absorbed or is not processed properly in the body. This causes symptoms such as abdominal pain or flatulence.

A common intolerance is the milk sugar (lactose) intolerance. In the process, the lactose in the intestine is not broken down and therefore can not enter the blood through the intestinal wall. Intestinal bacteria can also process this sugar without cleavage. This creates additional gases in the intestine. Common complaints of lactose intolerance are therefore abdominal pain and flatulence.

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Food allergy: symptoms

Food allergy symptoms can vary widely. Often reactions to the mucous membranes of the intestine, eye, nose and bronchial tubes as well as on the skin. Diarrhea, watery eyes, runny nose, asthma attacks with shortness of breath, rash, redness, swelling and itching of the skin often occur with a time delay.

In severe allergic reactions, life can be acutely threatened, so emergency medical help is required immediately. To be able to estimate the risk, allergic reactions are divided into different degrees of severity. On the basis of these groups, the therapy is planned and a possible risk to the patient is assessed.

Severity levels of food allergy:

Grade 0: In the lightest allergic reaction, only redness, swelling or itching of the mucous membranes that have been in contact with the food. There is no body-wide reaction.

Grade 1: The first degree of food allergy already leads to a whole body reaction. Rash, redness, wheals and itching are often first signs. It can also cause headaches, hoarseness and restlessness. There is no danger to life, but the patient should be closely monitored to detect any deterioration at an early stage.

Grade 2: In addition to the symptoms of the first degree, airlessness, dizziness, urine and stool urgency occur. The pulse is fast and the blood pressure low.

Grade 3: In addition to the complaints of the first two degrees, there is already a threatening shortness of breath. There is an involuntary loss of stool and urine. Often, those affected vomit. Their consciousness is clouded and they are only partially responsive.

Grade 4: In this medical emergency, the patient loses consciousness, suffers respiratory and circulatory arrest. The blood supply of vital organs collapses. There is an acute danger to life. Doctors in this situation speak of an anaphylactic shock. Such an allergic reaction requires immediate emergency medical intervention to save the patient.

Light food allergy symptoms are difficult to identify and often can only be clearly identified by a food allergy test. In many cases, the patient unnecessarily suffers for years from symptoms that can be easily avoided by the deliberate omission of certain foods.

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Food allergy: causes and risk factors

How and why some people develop food allergy is not completely clear yet. It is known that the predisposition is hereditary. Depending on which environmental stimuli are added, an allergy or not develops.

Upon contact with a certain substance from the food, the immune system is sensitized in unfavorable constellations against it. As a rule, these substances are proteins. Doctors call the allergenic substances: "allergens". Against these allergens certain immune cells form antibodies of the IgE type. When the human comes into contact with the antigen again, the antibodies activate so-called mast cells, which release histamine. The messenger histamine causes the mucous membranes to swell, itch and trigger a variety of inflammatory reactions in the body.

Protective breast milk

Breastfeeding offers good protection against food allergies. In particular, infants whose parents suffer from allergic diseases should be exclusively breastfed during the first six months of life. If you start the supplement earlier, your risk of food allergy increases.

Hygiene promotes allergies

In recent decades, allergies have significantly gained ground in the industrial nations. Reason for this could just be the pleasing hygienic conditions. Although it protects against other diseases, but may have the consequence that the immune system in the youth has too few training options. It then learns less well to distinguish between harmless and dangerous foreign substances. It then tolerates even less harmless foreign substances less well, which could promote the development of allergies. In fact, children who grow up in the countryside, especially on farms, are less likely to have allergies. People with parasites (such as worms in the gut) are less likely to get sick. Experts call this possible connection a hygiene hypothesis.

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Food allergy: examinations and diagnosis

Finding out if and, if so, under which food allergy a patient suffers is not always easy. The conversation with the patient and a detailed description of the symptoms provide the physician with important information. For example, if a patient suffers from hay fever or other allergic diseases, additional food allergy is more likely.

With a skin food allergy test, the doctor can test the response of the immune system to certain allergens, such as apple constituents. Components of various allergens are introduced into the skin via a small scribe. If the body reacts to an allergen during the food allergy test, skin becomes reddened. Depending on the severity and diameter of the redness, the doctor can assess the severity of the allergy.

In rare cases, a so-called provocation test is necessary. The patient takes under medical supervision a small amount of potentially allergenic food to him. The doctor closely monitors whether a reaction has occurred. If the reaction is severe, life-threatening anaphylactic shock can occur. In that case, the doctor must be able to respond immediately and administer appropriate medication.