Food allergy
synonym
Food allergy
Definition of food allergy
Under one Food allergy one understands one allergic reactioncaused by parts of certain foods. Allergic reactions are exaggerated Reactions of the Immune systemms on actually harmless components of our environment.
Food allergies are not allowed to use frequent Intolerancese.g. against lactose (Lactose intolerance), which are based on the fact that the body has an important enzyme for the degradation of the corresponding substance is missing. These are not Allergiesbecause that immune system is not active here.
Pathogenesis
The trigger for a food allergy is contact with actually harmless food components. These are mostly orally, i.e. through the mouth. In particularly severe cases, however, contact with the skin is sufficient.
The immune system responds to these so-called allergens as if they were bacteria or viruses that are harmful to the body. When it comes into contact with the allergen for the first time, the body scans the substance precisely with the help of certain cells so that it can accurately identify it from the second contact and initiate appropriate reactions.
Symptoms of an allergic reaction that only occur after the second contact can occur, for example:
- the skin as so-called hives,
- the mucous membranes (especially in the nose) and in this particular case
- also as gastrointestinal complaints.
These reactions, which feel very different for those affected, are all due to the same mechanisms in the respective tissues. Food allergies are often allergies of the so-called type 1 or immediate type:
Mast cells, certain White blood cells, carry receptors, i.e. proteins into which the allergen fits like a key in a lock, on their surface. As soon as a certain amount of the allergen is present, the cells release certain substances, so-called mediators, which signal the body and other immune cells that the substance must be removed or rendered harmless.
This includes that the vessels become more permeable. Therefore, more fluid gets into the tissue that surrounds the cells. Skin and mucous membranes (also mucous membranes within the body, e.g. in the intestines) swell. Liquid rises to the surface. In the case of hay fever, this leads to a runny nose and, in the case of allergens in food, also to diarrhea.
The swollen tissue also creates constrictions, which e.g. show as more difficult breathing. Not everyone has allergies, so it is assumed that genetic factors play an important role. This is particularly likely with this form of allergy, as it occurs very early.
Read about this too Allergic reaction
Allergens
In principle, almost all foods can trigger allergies. There are only a few exceptions for which no allergies have yet been described (e.g. rice). Food allergies to:
- Egg white,
- Cow milk and
- Nuts.
It is noticeable that food allergens are found mainly in high-fat foods, such as Nuts or eggs. There are already theories and studies that suggest that mechanisms of fat transport could be responsible for the development of these allergies.
Contact with the allergen almost always occurs through food, but there are also cases in which, for example, a milk bath could trigger a corresponding food allergy. Food allergies can also occur as a so-called cross-reaction with hay fever. This means that food allergens are so similar to pollen that the body reacts to both.
Also read about this:
- Milk allergy
- Allergy to apples
- Tomato allergy
Symptoms
Food allergies mainly occur in infancy and toddler age. It is therefore mostly the task and duty of the parents to interpret the corresponding signs and to correctly assess their danger.
A hives, i.e. Diffusely distributed, slightly reddened elevations, which are reminiscent of contact with a nettle and briefly disappear when brushed, can be a first indication of a previously undiscovered food allergy. But gastrointestinal complaints, which are by no means unusual in healthy children of this age, are also among the symptoms. It can too
- Vomit,
- Pain and
- Diarrhea coming.
If they exist for a long time, the children with food allergies also fail to thrive, i.e. one can notice a delay in the course after previously normal weight and height development. Such failure to thrive is always an important warning sign of potentially dangerous diseases and should definitely be clarified by a pediatrician. The above-mentioned intolerances (food intolerances) can lead to a similar picture and should therefore also be investigated.
You might also be interested in: You can recognize histamine intolerance by these symptoms
Symptoms on the skin
A food allergy can show up like other allergies. The skin can show rashes, redness, wheals, itching, tingling of the mucous membranes or swelling of the lips, for example.
Also read: Allergy on the face - what's behind it?
Symptoms of the bowel
Allergic symptoms in the gastrointestinal tract are mainly nausea, Vomit and above all: diarrhea. Also Weight loss can be a symptom of a severe food allergy.
Diarrhea as a symptom
Diarrhea is a symptom that is part of a food allergy frequently occurs. Usually the diarrhea stops a few hours after admission of the triggering food.
Food allergy rash
As already described above, symptoms that occur as part of a food allergy often manifest themselves on the skin. For example through itchy rash or Wheal formation. It can also cause an allergic reaction in the area Mucous membranes With itching come. Symptoms usually resolve after a few hours have passed since the triggering food was ingested.
Duration of symptoms
The acute symptoms of an allergy persist after ingestion of the food Minutes to hours on, but should within a few hours be gone again. In many cases, a food allergy in adulthood persists throughout life and does not resolve again.
How can you test for a food allergy?
You can also try to find out whether you are allergic to a certain food without medical help. It is important to have a kind Food diary to write. It should be noted what food you have eaten and whether symptoms have occurred.
If a certain food is suspected to be allergenic, this food should first be used for some time Removed completely from the menu become. Then a so-called Provocation test take place, so you eat the food again and observe whether allergic symptoms appear. At a pronounced allergy should be such a provocation however not without medical supervision as an allergic reaction, if left untreated, can lead to death in the worst case.
Allergists are doctors who mainly deal with allergic diseases. You can do various tests to determine if there is an allergy. A typical and widely used test is the so-called Prick test. Certain potential allergens are applied to the skin and, so to speak, scratched under the skin. After a certain period of time, a check is made to see whether any redness / wheal has formed on the skin. This would then be an indication of the presence of an allergy to the allergen tested.
What is the therapy of a food allergy like?
Treatment of a food allergy consists primarily in avoiding the offending food. However, this does not cure the disease. This means that the allergy will most likely reappear if you consume the food that triggered it again. If mild allergic symptoms develop to many foods, drug therapy with an antihistamine can be tried. This should be taken daily and should alleviate the symptoms that occur in the context of the allergy.
In rare cases, a so-called desensitization is also possible with a food allergy. Here, the triggering food is fed in small doses over and over again for months until the body has, so to speak, got used to it and no longer reacts allergically. However, desensitization can only be used for certain allergies, very rarely for food allergies.
People who have a strong allergic reaction, such as many people with a peanut allergy, should always have an emergency kit with them. This includes medication that can save lives in the event of an anaphylactic shock.
Read more on this topic at: Allergy emergency kit., Food allergy therapy
Food allergy in the baby
In babies, allergic reactions are the most common milk, nuts, flesh, fish and Eggs on. Also one Soy allergy has increased in toddlers and infants in recent years. The current assumption is that the PH value of the stomach plays a role in the development of allergies. Usually the pH in the stomach is relatively acidic. In infants and toddlers, however, this acidic environment has only developed End of the 2nd year of life fully developed.
In the context of an allergic reaction, small children and infants often react primarily with complaints in the gastrointestinal tract such as diarrhea and Vomit. If these symptoms are very pronounced and if the allergen continues to be supplied regularly, the symptoms can lead to a Growth retardation come.
For infants with a food allergy there are numerous, so-called hypoallergenic products on the market, it is called HA food. Most children lose food intolerance during the first years of life again. However, it can later lead to the development of other allergies such as hay fever come.
Food allergy in children
Infants who suffer from a food allergy tend to outgrow it, so most of the allergies of infancy and toddler age Disappeared by the age of 5 are. Young people and adults too mostly develop other types of allergies. The food allergies that exist in advanced age are often so-called Cross allergies. This means that there is already an allergy to a certain allergen, a common example being birch pollen. The antibodies that are formed by the body against surface molecules on the birch pollen and that ultimately trigger the allergic reaction can, however, also react to other, similar-looking molecules. Typical cross allergies in birch pollen allergy sufferers are, for example, an allergy to Apples and other things Pome fruit, nuts and soy.
However, there is also "real"Allergies in adolescence and adulthood, here in particular is that Peanut allergy to highlight. Food allergies in adolescence and adulthood are shown, for example, by a Tingling of the lining of the mouth or a Swelling of the lips. However, there are allergies that can be life threatening with Circulatory shock and Obstructed airways. One then speaks of one anaphylactic shock.
Classification of allergies
Allergies in general are in 4 types of allergies divided. They differ in how the allergy arises at the molecular level. Outwardly they differ in the Duration between allergen contact and the first appearance of symptoms.
Type I is the allergy from Immediate type. The symptoms recur Seconds to minutes on. Type II is called cytotoxic type designated. Symptoms appear after about 6-12 hours on. In the case of type III allergies, Immune complexes. Symptoms appear here too 6-12 hours on. Type IV describes an allergy from delayed type. Symptoms appear 12-72 hours on.
An example of a type IV allergy is this Drug eruption, a rash that can develop after contact with a drug. However, there are also rashes after taking medication that appear after a few minutes, i.e. they belong to type I allergies. Like types II and III, type IV allergies are rather rare, type I allergy is by far the most common. Also the Food allergy is type I.. Other type I allergies are hay fever and allergic asthma.
