Gentowa

The skin tests are necessary supplements of all basic allergist examinations. The allergic hypersensitiveness proof was discovered by Charlie Blackley already in 1865. The technique

was later on improved by Grant Lewis, Pepyes and others, who introduced the prick test (stinger) usage. Nowadays the standardized method introduced by the European allergist and clinical immunology academy.

The skin test in based on the fact, that sensitive allergic patient has specific antibodies against the allergens not only in the particular organ, in which the clinical symptoms are active, but also in the cell membrane – mastocyte which are in the skin. While testing, the suspect allergen is injected into the patients´ skin near the forearm. The allergen choice is made according to the patients´ data on the clinical symptoms period. The standard group of allergens, which includes the following, is used:

● trees pollen

● grass pollen

● rye

● worm wood

● ambrosia

● mould

● feather

● mites

● positive control (histamine)

● negative control (usually a solution with dissolved allergens)

According to the seasonality, others allergens are added. If the patient is in the contact with the animals, the animal allergens (dog, cat, etc) are tested, as well. Before the testing the patient should cease the anti allergic treatment (the antihistamines for at least one week), but others, as well. For example many preparations used by the psychiatrists relieve even the skin reaction at the skin tests.

When possible, the patient should be tested even off pollen season. It is not appropriate to test somebody during or right after the infection since it can cover the reaction, as well. For checking the skin test realisation correctness beside the allergens, the positive and the negative control is injected. As the positive control histamine is used – a chemical, which is released during the allergic reaction in general, i.e. test with this chemical can be positive even in the case of the health people. If this reaction after the testing is negative, the test is not valid, since some of the processes or the medications relieved all reactions.

The negative checking is, on the contrary, is injected in order to exclude the reaction, which is only mechanical – the injury or the injection itself, or the allergic reaction to the solution, eventually to the conservative chemical in the allergen solution. The skin tests allergens are made commercially. Their content and dilution are standardised.

How does the skin test reaction look like?

The applied allergens are bound on the antibodies molecules IgE - on the outside part of the mastocytes and through the transfer of the signal their degranulation and the allergic reaction mediators release occur. These initiate the reaction through the affect on the surrounding blood vessels, the symptoms of which are the flush, the itch and the swelling with the diameter of several millimetres in the place of the injection. On the reaction, which starts approximately after 5 minutes from the allergen application, takes part also the so called substance P, which is released from the sensitive nerve ending, after the histamine stimulation. The reaction culminates in the period of 15-20 minutes, when the doctor subtracts it, after this time the reaction decreases.

The skin test realisation is not painful for the patient. On the palm side of the forearm the drops of the examining allergens are applied. In every drop a gentle puncture with the plastic or metal tool with the small sharp top is made. The skin is punctured only on the top skin layer so that the place does not have to bleed at all. After 20 minutes the reaction is judged. Places, which are either red or swollen in the same way as after applying the histamine, indicate that the reaction is positive. The patient can react to one or ore allergens. Beside the reaction when the small papule with the diameter of several millimetres appear, which is the most common reaction, the more extensive local reaction – of several centimetres, in rare cases even the swelling of the hand come about. These reactions cease to occur spontaneously after several hours.

In addition to the immediate reaction the patient can react in the so called later phase, when the papules appear after several hours. The patient deducts and informs the doctor of the reaction by himself/herself. The skin tests represent the allergist diagnosis basis. Together with the detailed taken anamnesis they are sufficient for the majority of the patients sensitive to common inhalation allergens for the typical symptoms of the diagnosis. Their role in the diagnosis is hence important, which relates to the fact that their preparation and realisation should be paid attention to.

The skin tests can be characterised as indirect provoking tests. They are called indirect, since their positives and negatives prove the sensitization of the human body. The presence of the specific IgE antibodies to applied allergen is proved on the skin without giving the information on the reactivity of the particular target organ (unless the target organ is the skin itself). Standard prick tests are used. They are made by the pharmaceutical companies, which prepare them according to the strict formulas. The content of all solutions with the allergens is diluted exactly together with the known analysed components of the particular chemical. The food allergens to the prick tests are chosen similar according to the patients. In the basic scale the eggs, nuts, milk and hesperidium should not be omitted. As far as the patient has not only a food allergy, but also the inhalational allergy, we add the cross reacting foodstuffs (birch-apple, Artemisia-celery, mites-crabs, latex-banana, etc.).

The professional airways allergic illnesses have increasing tendency. The allergens are represented by the whole range of various factors of both, the vegetable and animal origin, but also by the chemical agents. Besides the pharmacotherapy, which does not differ from the common recommended procedures, the fundamental step is the immediate transfer of the patient from the exposition of the cause, which is necessary to be defined. To the testing process the chemicals, which are not tested with the traditional patients, are added, as well.

The contact allergy diagnosis skin tests are made by putting the analysed chemical on the skin. More information is provided in the chapter about the contact allergy.

Red and white beans

are often food components used in sauces or soups. They are oftenadded to canned meat food products. The patients often cross-react to other kinds of legumes,as well.

Soya beans are the most frequently used legume worldwide. Soya is used in various forms– starting with the traditional legumes, continuing with prepared foodstuff – tofu, soya fibre,soya “meat”. The soya sauce is a part of mixed sauces and dressings. According to itsfrequent usage it belongs to the most common causes of the allergic reactions. Moreover, thedisoriented patients, especially the parents of children suffering some allergies think that soyamilk can substitute the cows´ milk. The reverse is true! Offering another allergen, althoughany cross-reaction is threatening, is unsuitable for children.

The cross-reaction occurs withpeas, peanuts and other legumes.Meals which can contain the soya protein:

● ready made baby food

● bakery products

● pudding

● bread

● hamburger

● butter adjunct

● chocolate

● meat products

● sausages

● soups

● crackers

● dressings

● deserts

● ice-cream

● canned meat

● caned fish

Peas and lentils

do not belong to often allergens in these latitudes (in India it is the fifthmost common allergen). Those allergic to these legumes should be careful. Peas are added tovarious meals, for example mayonnaise and sandwiches.

Peanuts (groundnuts)

belong to the most common food allergens at all. In the UnitedStates it is the number one in particular because of the fact, that the peanut butter iscommonly used in American cuisine. This vice has already appeared in Europe – just think ofall the Nutela peanut butters and other sweet spreads, waffle fillings, etc.The peanut as an allergen is dangerous since its oil is added to the whole range offoodstuffs, while, unfortunately, this information is not written on the cover of the foodstuff!This goes for various sauces, cakes, ice-creams and flavours. It is often used for thickeningthe meals – mostly various barbecue sauces. Traces of peanuts allergens are marked even infoodstuffs, which do not contain any peanuts at all – as a result of the previous productionprocess of the production devices. After eating such foodstuff, a serious allergic reaction wasprecipitated. In the United States several tens of people die as a result of the anaphylacticshock after eating the peanuts or their parts.The cross-reaction can occur with other legumes.

Nuts and seeds

Many seeds inside the shells are regarded as nuts, although from the botanic point ofview they do not belong to this group of fruit. As foodstuff they are used commonlywhether as food supplements because of their high level of proteins and oils, or becauseof their taste.

The seeds and nuts are often allergens and danger the allergic people perhaps the mostbecause they are contained in many food products. The various bakery products – breads,pastry, cakes, cereals, candies, sweets, ice-creams, drinks, chocolate products, desserts, milkproducts and hundreds other products contain some of the nuts or seeds. The great danger forthe allergic people lies in the fact that many products contain such a small amount of theseelements so that the producer does not declare it. The patients allergic to some of thefollowing seeds or nuts have to be very careful while choosing their foodstuffs.

Almonds

are stone fruit kernels of typical taste. According to the presence or absence of theglycoside, which is called amygdaline, they are divided into bitter and sweet types. Thekernels are eaten either alone – roasted and salted or added to various products – ice-creams,chocolates, cakes, puddings, chew gums. Be careful – the almond oil is often added tocosmetic products.

Brazil nuts

are actually seeds from huge trees, growing in the wildness of the SouthAmerica and in the rain forests of the Amazon region. The trees are not planted, but the cropand the export of the seeds forms an important part of their economy. Inside the big fruit-up totwo kilograms of weigh- with the wooden shell, 10-22 seeds are growing. The nuts with ahigh nutritional value and 60 or more percentage content of the oil and 17% of the proteins.

Food of vegetable origin Cereals

Common cereal seeds are well known allergens. In addition to the sugar, they consistof proteins, which are most responsible for the allergic reaction. Barley, wheat, rye, corn, rice,oat and millet are counted here. The reaction by which the human body is allergic to proteinsof barley, wheat and rye – gluten and gliadin should be distinguished from the classicalallergic reactions. This disease is caused by innate metabolism anomaly.

Barley

is often planted cereal for it is not only a component of the food chain, but also acereal the liquors are made of. The patients allergic to barley products and often to liquorscross-react to ray and wheat. Be careful with the beer.

Malt, mostly made of barley, is a number of germinated, dried, and ground cereal grains. Atthis process it comes to changes. Many sugars and proteins of the original cereals aredenaturalised. In addition to the production of beer and whisky, the malt is being used also asan adjunct to cereals (flakes) and filling of different cakes.

Buckwheat

does not belong to the true cereals. In Europe it belongs to often used foodstuff.It is used in the pancake filling and other pasta (spaghetti, macaroni) and is part of many babyfood products. In Japan the buckwheat belongs to major allergens – it is often used in thenoodles.

Corn

comes from America, from which it spread to the whole world. It is used in a range offoodstuff products from corn flour, but also boiled – independently, or in salads. It is often acomponent of the baby food products. The corn flour fills many foodstuff products. Whiskeyof the bourbon type (USA) is made of corn flour.

Millet

is used in Europe not so often. It is used especially in Asia. For example in India it isconsumed more frequent than the wheat in European countries. Since it cross-reacts only rarewith other cereals, this type of cereal can be used as a substitution to patients who are allergicto wheat or rice.

Oat

belongs in the last decades to frequently used foodstuff – especially as an advantageousfibrous food adjunct for example in the form of flakes typically prepared for the breakfast.It is used in soups, sauces, yogurts and different types of foodstuff.

Rice

is a basic food component of more than half of the human population. It comprises 20%of all calories consumed per day in the world. The rice flour is used as a starchy filling in therange of food products. Fortunately it does not belong to often food allergens.

Wheat

probably belongs to the most used food components in the world. Starting withtraditional bread, bakery products, cakes made from leavened dough (Europe, NorthAmerica), unleavened baked goods and pancakes (South America, Asia), pasta like couscous(Africa, Near East), macaroni, noodles, pasta (Mediterranean) – we can find wheat products inthe whole world. Wheat is very often – as so called “hidden allergen” used in other foodproducts. It is added to sausages, various smoked meat products, chips, fast food products,sauces – (commercially sold for example soya sauce) and candies. Since the sensitiveness atwheat is not rare in the case of both, adults and children, it is necessary to avoid food productscalled fast food, where even the seller need not to be aware of the information on thepresence of the wheat flour!The patients allergic to wheat can replace the wheat with rice or corn flour products.

Legumes

To these wide spread food products the following can be counted: read beans, white beans,soya beans, lentils, peas, peanuts, gum Arabic, fennel, liquorice (black sweet) . In addition topeanuts, which can be regarded as the most important food allergen, the legumes do notbelong to often causes of allergic reactions.