- Reasons of food allergy
- Symptoms of food allergy
- Treatment of food allergy
- Prevention of food allergy
Food allergy is a reaction of sensitivity of immune system of the person to a certain food (food stuff).
In the presence of food allergy immunoglobulins E (IgE) – the antibodies necessary for allergen destruction are produced. The histamine is thus developed. An organism, having cellular memory, every time when faces allergen develops a histamine. There are allergy symptoms which cover various areas of a body: skin, in respiratory organs, a nervous system and digestive organs. The digestive disturbance after food of specific products not always is an allergy. These reactions can be food hypersensitivity or intolerance. They can also be symptoms of other, more serious diseases of the alimentary system.
About 90% of cases of food allergy are caused by wheat, a peanut, nuts, milk, eggs, mollusks, soy and fish. Many other products can become the reason of food allergy or reaction of hypersensitivity, for example berries, fruit, tomatoes, corn and some grades of meat. Migraine can be connected with sensitivity to the chemicals which are contained in red wine, meat delicacies, the matured cheeses and the tannin which is contained in tea.
Usually, when the child has an allergy to one food stuff of a certain group, it most likely will react also to other products in this food group. For example, if the child is sensitive to one species of fish, it can be sensitive also to other types. It is called cross-responsiveness.
Every year about 200 children and adults in the USA die of the anaphylaxis connected with foodstuff – heavy allergic reaction which causes hypostasis of a throat and bronchial ways, shock and sharp falling of arterial pressure.
The genetics also plays an important role in development of food allergy. If one of parents has this pathology, the risk of the child to ache increases twice. If both parents have food allergy, then the risk is even higher. The child, however, can have an allergy to absolutely other food from that to which the parent is sensitive.
Reasons of food allergy:
Allergies are caused by reaction of immune system to specific food.
The food intolerance is often referred to food allergy though it can develop by other principle. In these cases digestive tract reacts to a certain component of a product, for example, protein or sugar. Abdominal distention, a gastric disturbance, diarrhea, nausea or vomiting results. Often this reaction is caused by planting of food bacteria, but not a true allergy to food. In other cases reaction of the child is connected with the main pathology of the alimentary system, for example, a syndrome of the angry intestines which is a chronic disease.
Some children can not have the specific enzyme necessary for metabolism of certain products. About 10 percent of all adults and children of advanced age have a lactose intolerance. There are two forms of a lactose intolerance: inborn and acquired. The hereditary form (autosomal and recessive) of this pathology is extremely rare and serious illness. This pathology is not life-threatening, however can bring to the patient discomfort. It is more often observed at the Afro-Americans. Sometimes children, and happens also adults, have a transitional form of deficit of lactose which develops after a diarrhea episode.
Children with a lactose intolerance have deficit of lactase which provides digestion of milk and dairy products. Some children can drink milk which incorporates acidophilic bacteria. These bacteria destroys lactose, or milk sugar. Some children with a lactose intolerance cannot drink whole milk, but use cheese and the fat-free kefir in small amounts. Such state differs from a true allergy to milk at which even in a small amount any dairy product will cause reaction.
Some children can not transfer food dyes, additives and preservatives. Among them yellow dye No. 5 which can cause a small tortoiseshell, and the sodium glutamate capable to lead to a headache and a stethalgia matters. Sulfites, other additive, can be the reason of asthmatic and even anaphylactoid reactions. Sulfites are preservatives, used in wines, seafood and soft drinks. Sometimes they are added to fresh fruit and salads for maintenance of their fresh look, to red meat to prevent its darkening, and even in already ready salads. Sulfites are designated on labels as sodium sulfite, sodium bisulphite, potassium bisulphite, sulfur dioxide and potassium metabisulphite.
Symptoms of food allergy:
Food allergies and hypersensitivity can be followed by a wide range of the symptoms connected with skin, airways and a nervous system. At children the watering eyes, cold and sneezing can be shown.
Skin rashes or urticaria need to be differentiated from measles and other infectious diseases. Rash can develop on a certain part of a body, or can be eurysynusic. Sometimes there is hypostasis of eyes, lips and/or language.
At different patients symptoms quite often vary even if sensitivity to the same product is defined. However it is noted that nut and mollusks are the most widespread triggers of an anaphylaxis. Nevertheless, the anaphylaxis is not limited to these reasons. The IgE-mediated allergic reactions can progress to other allergic symptoms.
Symptoms also differ on the intensity. One child can have a moderate rash on forearms if he ate a large number of strawberry. At the same time other child from its small amount has a widespread expressed rash.
In most cases symptoms arise within several hours after consumption of a food-borne allergen. Reactions of a lactose intolerance can be shown a bit later.
The acute anaphylaxis is extreme reaction to food, as a rule, on a peanut and nuts. Reaction is followed by hypostasis of a throat and bronchial ways, falling of arterial pressure, shock and even death. The child with an anaphylaxis needs to give help in the shortest terms.
At any displays of an allergy it is necessary to see a doctor. Special attention is paid to digestive symptoms, neurologic symptoms, especially a headache are not less important.
At the first displays of an allergy it is necessary to identify food allergen that will allow to exclude it from a diet as soon as possible.
Skin allergological tests represent a series of pricks on the child's skin by means of the plastic applicator which contains allergen in the concentrated look. Food allergy is diagnosed if skin of the child reacts a papule or reddening. Skin allergological tests for foodstuff (not for aeroallergens) have the high frequency of false positive answers, that is, the test can be positive, but the child is not truly allergic persons, or have no symptoms. This test is not used at children from heavy anaphylactic reaction or eurysynusic eczema.
The allergist can also make an experiment for detection of an allergy. The child accepts the suspected product in the increasing quantities to see what reaction happens.
One of tests allergists call RAST (Radio-Allergo-Sorbent Test). It measures quantity of antibodies of IgE in blood which is made on some the known food-borne allergens. As well as skin аллерготест, RAST and other tests for antibodies have the high level of false positive results.
Also doctors recommend restrictions in a diet. Basic diet at the same time represents a series of products which are not allergy triggers. This diet consists of products, such as mutton, fowl, rice, vegetables and all fruit, except a citrus and berries. Every week enter one new product into a diet. Reaction the patient is weekly written down. If the child has no reaction, the product is considered safe and can remain in a diet. If there is a reaction, this product is excluded from a diet.
Treatment of food allergy:
Only for treatment of the IgE-mediated reactions to foodstuff the product exception of a diet is reasonable. These reactions, and also reactions of intolerance, do not react to desensitization. At all allergic persons with so-called IgE the mediated reactions has to be at itself "Epi handle" (the syringe with Epinephrinum).
Usually children want to eat that product on which at it an allergy. When the child is on an eliminative diet, thirst for such products is observed.
Some doctors appoint antihistaminic drugs to help to reduce symptoms. However it is necessary to remember that these drugs are intended for use in case of manifestation of symptoms of an allergy, but not for the long period of use.
Elimination of one product will not influence its development in any way. There is a sufficient variety of products which are interchangeable. To some foodstuff, however, can be difficult to find replacement. It is especially difficult to replace wheat though bread, the macaroni, confectionery and products prepared from oat and rice flour are good substitutes.
Children, as we know, in most cases "outgrow" an allergy to milk. Disappearance of an allergy to eggs it is not so high, as well as for an allergy to milk. Sensitivity to wheat and soy can also decrease or at all disappear. The allergy to a peanut, seafood and other products which can lead to an anaphylaxis usually remains at the child throughout all life.
Prevention of food allergy:
If both parents have food allergy, it is necessary to take precautionary measures to minimize risk to ache for the child. Before childbirth and during feeding by a breast mother can limit impact of the child on allergens, without using the known products - allergens in food. Breastfeeding detains the beginning of an allergy, but does not prevent it. Secretory IgA in breast milk struggle with an infection, but does not reduce risk of development of an allergy.
Firm products slowly enter into the child's diet at the age of 4-6 months. The first feeding up has to consist of products which usually I do not cause an allergy - fruit (except citrus fruit and berries), vegetables and rice. Early introduction of highly allergenic products can cause reaction in the child, but it is disputable. It is recommended that parents avoided feeding of the child highly allergenic products up to three years if it is possible. The list highly allergenic products includes nuts, a peanut, fish, mollusks and eggs. Whole cow's milk is not given within the first year of life.