My friend who is an allergy specialist has helped me in creating this article. Our casual talk with regard to allergy and its medicines has encouraged us to create and publish this article. Myself is a skin allergy patient and i am continuing medicines to get rid of the same, so my personal experiences are also included in the article.
An allergy is a hypersensitivity of the disease-causing organism to harmless substances from the environment itself. Always preceded by a specific change in the defense system of the body, which can manifest itself later in an exaggerated reaction of the immune system. This process is also called sensitization. The exaggerated immune response as an allergic reaction After raising the immune system classifies then actually harmless substance as hazardous. Repeated exposure to the same substance, the allergen leads, subsequently reacted with an already formed by the body against substances (mostly antibodies). The term “allergy” has just celebrated its centenary. In 1906, led the Austrian pediatrician and professor of bacteriology, immunology and nutrition customer Clemens Peter Freiherr von Pirquet (1874-1929) the term “allergy” for the first time in the medical language. Pirquet defined allergy as “different reaction of the organism than the expected further to an immune response in the body vorgegangenen”. The word allergy is borrowed from the Greek language and means something like “foreign reaction” or “different response” (allo / s = strange, different, ergo / ergeia = reaction, work).
The allergic immune response to allergens (allergy-causing substances) can take place in different areas of the body. May be affected include the skin, the nose and throat, the respiratory tract, the gastrointestinal tract or the entire organism.
Also, the clinical pictures of allergy are very diverse. Known to almost everyone is the hay fever with the allergic inflammation of the nose and conjunctiva (allergic rhinitis and allergic conjunctivitis). A runny nose, the eyes burn and tear. By the dreaded floor change can arise from allergic asthma, which leads to breathlessness and quality of life can significantly reduce. In allergic reactions of the skin, contact dermatitis with itching and inflammation form or Atopic dermatitis (eczema). May also be affected the mouth and throat. Life-threatening allergic shock is the (anaphylaxis) brings including the cardiovascular system at risk.
What symptoms are triggered in an allergic person does not depend primarily on the allergen. The same substance may cause very different people different syndromes.
In principle cause (almost) any substance an allergic reaction. Often exogenous proteins (proteins) are triggers of allergy. It may be at the allergens but also involve metals, drugs or many other natural or synthetic substances. Currently, about 20,000 of these allergy-triggering substances are known. The search for the responsible allergen is therefore a challenge.
It is not possible to classify substances in “allergenic” and “non-allergenic” substances. Basically, almost any substance to the allergen. If and when this happens is not to predict. It depends on many factors: eg the type of action, ie the presence of allergens, their quantity and the time in which they act on the body as well as an awareness-promoting environments (wet work, smoke, etc.). However, there are substances that are much more likely to cause a sensitization and thus to a possible allergy, than others. Also predisposition, skin texture, age and sex of those affected be involved in deciding whether there is an awareness or not. Example Age: In youth about new cases are generally more common than hay fever with age. Of occupational allergies, however, are mostly adults, so older groups of people are affected. Example Sex differences: The contact allergy to nickel affects far more women than men.
The list of possible allergen types is long. It may be pollen or latex to excretions of dust mites, dander and saliva of animals to molds or chemicals (eg, PPD or from the textile finishing) to insect venom of bees or wasps to components of food (eg as seafood, peanuts, celery), but also drugs such as penicillin, perfumes or medicinal plants.
Allergens are substances that trigger an allergy. In most cases, these are exogenous proteins that the immune system as “foreign”, potentially dangerous and are therefore classified as “bekämpfenswert”. Contact allergens, however, are mostly fat-soluble substances, small molecules or ions that penetrate into tissue and bind to endogenous protein structures. Allergenic trigger an immune reaction. Immune cells that are distributed massively, especially histamine. Many allergens have a natural origin, such as pollen or insecticides. Others are synthetic. Many occur widely on (eg, pollen, dust mites, nickel), with another one comes in contact frequently in certain occupations. Very many allergens have been identified and explained in its structure. Yet science can not yet answer the question exactly what makes an allergen to allergen and why significant differences in the “allergenic potency” exist. And although it is now many thousands knows (about 20,000) allergens, is the group of “top allergens” relatively straightforward, which is responsible for nearly 90 percent of all allergies. Firstly, there are pollen of flowering grasses, trees and shrubs, mite droppings, animal dander and saliva (pets) as well as molds. For most of skin contact allergies nickel is responsible. There are also jobs with high allergen load about with flour or wood dust, metal ions such as chromates, epoxy or cement.
Duration and intensity of exposure to an allergen to determine the risk of developing sensitization. So who is frequently exposed to large amounts of an allergen, has a greater risk of developing an allergy. This dose-response relationship has been demonstrated for a number of occupational and environmental allergens. It plays, however, often from very low and barely measurable areas. Studies that have identified certain substances called thresholds, ie those allergen concentrations below which the risk of developing sensitization are very small, yet rare. Thresholds below which it is safe from sensitization and allergy, does not yet exist.
The immune system of the body has the very important task of protecting the body against disease-causing factors. Foreign, potentially pathogenic substances or micro-organisms (bacteria, viruses, fungi) are recognized by the immune system attacked and rendered harmless. Penetrate in the course of an infectious disease pathogens into the body or the cells are immune cells, antibodies and neurotransmitters on hand to take the attackers to do away with and protect the body and its organs from damage. Harmless substances can the immune cells of the body, usually on the left. Pollen, latex powder, and nuts provide the organism is not dangerous, and the immune system of a healthy person makes contact with such substances completely cold. But sometimes fails to distinguish between harmless and dangerous. And so it may develop an immune response against itself completely harmless substances, so come to raise awareness and as a result of an allergic reaction. Once this is done, the body reacts with every new contact with this specific substance with disease symptoms. Because the immune system a “memory”.
An allergic reaction is a little like Don Quixote fighting against the windmills. The deeper meaning of the “courageous struggle” remains hidden.
Why the immune system responds to certain (potential) allergens, other not, and why – with the same allergen exposure – which gets a one hay fever and other allergic to nickel, has still not been resolved scientifically.
An allergic reaction is always preceded by a sensitization. Here by contact with a potential allergen in the immune system an immune response takes place. It means that a substance (pollen, insect venom, metal) identified as potentially dangerous and the immune system for subsequent fight with renewed contact is made ready. In this first contact with the allergen yet there are no signs of illness. The sensitization to an allergen is a complex physiological process. It can be reduced with respect to the example of contact allergy in some described as follows: To protect against infections, immune cells are present in the skin. There are, inter alia, resting T cells, which are waiting for a task. If these T-cells by some other cells of the immune system, the so-called antigen presenting cells, they become known as effector cells. They recognize a specific substance (antigen) as bekämpfenswert. You can then use the allergen are rapidly activated and trigger an immune response when it is again exposed to the skin. The unpleasant consequence: an inflammatory reaction of the skin, allergic contact eczema.
Allergic contact reaction then proceeds again as follows: Splits a substance (hapten) to a protein structure of the skin, and this combination of hapten and amino acid sequence of the protein of the T-cells (as bekämpfenswert) recognized release these immune mediators, in turn, in a chain reaction trigger the release of other neurotransmitters and ultimately the inflammatory skin reaction, with the described symptoms of contact allergy, have resulted.
In the case of hay fever, asthma and insect bites stimulate cytokines (immune mediators of inflammation) of the T helper cells called B-cells to produce allergen-specific immunoglobulin (IgE). The formed IgE binds to the cell surface of mast cells and other immune cells. It recognizes by now to the allergen and triggers would again contact with allergens from the allergic reaction.
Not every sensitization resulting in allergic symptoms. A great many people who are on one or some equally sensitized to a variety of allergens ill, not for life. The background for this are still unclear. Should the investigation has found sensitization to specific allergens, this does not necessarily mean that the person concerned must be treated as ill-allergenic.
If the body again after sensitization in contact with the allergen, the IgE bound to mast cells into action. They scavenge the allergen and release highly active immune messengers. The most important messenger in many allergy is histamine. It causes typical allergic symptoms. Of hay fever and allergic asthma, food allergies and insect bites, the reaction develops within minutes after exposure to the allergen (immediate type). When contact allergy, it takes many hours or days (delayed). Here play other neurotransmitters and immune cells play a role. In severe allergic reactions to some insecticides can lead to cardiovascular failure and loss of consciousness (anaphylactic shock). If the person is not treated immediately, such an anaphylactic shock even death. Had already been entered into anaphylactic shock, should the person concerned, especially bee and wasp sting allergies, absolutely always carry an emergency kit with medicines for immediate self-treatment of himself. They include: antihistamines, cortisone and adrenaline spray. The dermatologist can possibly with a specific immunotherapy (SIT, desensitization) normalize the overreaction of the immune system location.
The predisposition to develop allergies is inherited. Whether in the course of life of allergy developed thus depends among other things on what genes you have noticed from his ancestors. If parents or siblings suffer from allergies, the risk is greater for a child, even to get one.
A personal or familial tendency to produce in response to contact with small amounts of an allergen with immunoglobulin E (IgE), is referred to as atopy. Typical examples of atopy are hay fever, allergic asthma and atopic eczema.
If both parents have the same allergy, the risk is for the children, also to develop these allergies in about 50 to 70 percent. Well as environmental factors play an important role in the development of allergies. If both parents are non-allergenic, the risk is for the children only between five and 15 percent. One allergic parent or sibling increases genetic predisposition already on about 20 to 35 (40) percent. If both parents have allergies, but different, one starts with a risk of allergies in children for 40 to 60 percent. The persons concerned are called atopy. What kind of allergy in the child forms, but is not inherited. Only the general tendency is in the genes.
Children who grow up on farms have a lot of siblings or are included early on in the nursery, get fewer allergies, eg so allergic asthma and atopic dermatitis. The studies have found: It seems to be important that the contact about to stall and milk takes place before the first birthday, and ideally at least five years will continue. Even in countries where infectious diseases are more common, there are fewer allergies.
The science explained it this way: In the industrialized countries, with their high standards of hygiene have little contact with children to hazardous antigens as non pathogenic microbes or parasites harmless. Your immune system does not have enough opportunity to learn from dangerous or hazardous distinction is even underemployed and seeks replacement opponent. We have very good hygiene standards presumably “side effects”. Early infections in terms of infectious diseases in the first six months of life, increase the risk of getting a disease atopic: note also is.
Researchers also think about how you can replace the missing children, the extended family farm or immunologically, to protect against allergies. They want to bring the body with specific antigens of bacteria, viruses or fungi, specifically in contact to guide the development of the immune system in the right direction and so to slow the allergic tendency. Since no one thinks of children unnecessarily exposing infections, researchers are looking for components of pathogens that could train the immune system through a kind of vaccination without causing illness. One of these substances is the endotoxin from the cell wall of gram-negative bacteria that have been found in clusters in the beds Bavarian farms. A second candidate is the BCG tuberculosis antigen, which has been tested in animal experiments in Japan.
From East Germany is likely that roundworm infections possibly before the turn of the children could have protected in the former GDR from allergies. Corresponding IgE antibodies to Ascaris had been there to see the fall of the Iron Curtain, much more common than in the West, however, much less common allergies. In studies provide scientists with high-risk children in the first months after birth, for example, now endotoxinhaltige drops for allergy and asthma prevention. With significant results of such studies is, however, only expected in a few years.
Overall, the hygiene hypothesis has to be differentiated. Other studies suggest that there is not so much the quantity of microorganisms important in which an infant comes in contact, but that it must be the “right”. British scientists have about particular microbial strains in the visor, which is living with a man for thousands of years as symbiotic lactobacilli, mycobacteria, and a number of other microbes. Only in contact with the immune system to these microorganisms seem to be able to configure the number of its function, and T-helper cells, and to properly control. Otherwise you lose the immune tolerance.
What can I, what can parents do to prevent the formation of an allergy in their child? In the science still knows too little. The current concepts rely on the avoidance of risk factors and strengthening protective factors.
Prevention can help:
Breastfeeding for the first six months
If breastfeeding is not possible: feeding hypoallergenic infant formula
No smoking of the mother during pregnancy and lactation – and possibly beyond. Smoking during pregnancy fosters the development of allergy in children. It is best if Dad also participates.
Avoid early childhood contact with pets: for allergy risk children
The only causal (counteracting the causes) therapy for allergies is immunotherapy, in medicine also called specific immunotherapy (SIT). It extracts of different pollen, dust mites, animal dander, insect stings and molds over a period of about three years regularly in small, increasing doses under the skin (subcutaneously) was injected into the upper arm. Initially follows a weekly injection (induction phase) with the allergen preparation, after seven to twelve weeks to once a month (maintenance dose). Used is a standardized allergen preparation with the substance to which the patient is allergic. By gradual habituation one tries so as to bring the immune system to be less (hypo) sensitive (sensitive) to the allergens. This has many positive effects: The drug consumption is reduced and worse can be averted in the rule: If hay fever is down about the risk of floor change to allergic asthma in insect allergies could lead to anaphylactic shock. With the help of the SIT, however, the tolerance of the immune system are recovered. This leads to a decline in complaints and brings lost quality of life back. And it prevents worse consequences of allergy. Medical research now works also due to be replaced by spraying droplets or allergen tablets. For example, grass which is already succeeded. The treatment solution or tablet is placed here in the mouth under the tongue and left there for some time and then swallowed or spit out. This must at first daily, later still happen every three days. Here, too, increases the dose slowly. Sublingual immunotherapy for these (SLIT), it takes about one and a half year period.
With hay fever can show the success rates of dermatologists hyposensitization of 80 to 90 percent. During induction of SIT and SLIT, allergic symptoms occur. This limited but mostly itching and swelling at the injection site. Impairments are rare in the general condition such as fatigue or headache. Allergic reactions such as hives, difficulty breathing, circulatory problems or the occurrence of eczema can not be excluded.
Advantage of sublingual immunotherapy: it is painless, the victims do not have to regularly visit a surgery or hospital to save time. The risk of allergic shock and other side effects are extremely small. However, missing for many allergens are studies and long-term experience. The SLIT but in Germany has not granted the same status as the “injection therapy.” But scientists worldwide agree that it is a promising alternative.
Although you can also relieve the symptoms of allergy with various medicines, but sufferers are always at risk of developing known or new symptoms to an allergic shock. The drugs only treat the symptoms but not the cause of an allergy. Against the symptoms of allergies especially help antihistamines or cortisone. Cromoglycate (DSCG) in eye and nose drops or nasal sprays to reduce the release of histamine from mast cells. And psychological treatments can help relieve symptoms.
In hay fever patients with an allergy to pollen specific physicians observed more frequently known as a cross-allergy. These patients also react to certain foods with symptoms of allergy such as burning, itching, or tingling of the lips, palate or throat. The allergens of grasses, herbs and tree pollens are similar in structure to particular proteins from fruit or vegetables. The immune system is sensitized to an allergen pollen, it also comes in contact with similar structures from other plants to the allergic reaction. Tree pollen allergies tolerate example often not different fruits like apples, cherries, plums, kiwi and strawberries. Nuts too can cause problems. Grass pollen allergy sufferers, the consumption of cereals and legumes such as peanuts or soy cause problems. To mugwort pollen-sensitized or other herbs may not tolerate contact with celery, carrots and various spices. The consumption of bananas, kiwis and avocados can be uncomfortable for latex allergy. Seafood is nothing for some of the people with allergy to dust mites. Even when the cross allergy desensitization or specific immunotherapy (SIT) is the treatment of choice, which promises permanent improvement. Early origins of the SIT allergy, hay fever, for example, can prevent the emergence of a cross-allergy.
Allergies are on the rise worldwide. The number of patients has increased steadily in recent decades. And a multitude of epidemiological surveys suggests that allergic diseases in developed countries continue to increase. The number of people who suffer allergic bronchial asthma had doubled in the 1980s alone already. During the late 1920s, only one to two percent of people suffering from hay fever, there are already twelve percent. In 1900, the overall rate for all allergies in Germany had been as high as two percent. And this frequency was increased up to the fifties only marginally. With industrialization in the West, however, took the allergy rate in the West steadily until today. In Germany today is estimated that about 25 million people are affected by allergies. For the increase in variety of environmental factors are held responsible, which brings modern lifestyles with them. These include environmental pollutants, very high standard of hygiene, increased allergen exposure to aeroallergens. Among the environmental pollutants, air pollution play by ozone, sulfur dioxide, nitrogen oxides and particulates from diesel exhaust and industrial role, but also the cigarette smoke. The influence of infectious diseases of childhood, the environment in which the child has been removed or vaccinations are discussed as factors.
For an influence of lifestyle, for example, is supported by the fact that the incidence of allergy and asthma disorders in children and adolescents in East and West Germany has adapted in recent years almost. Within a few years, the number of atopic diseases in East Germany has almost doubled. The incidence of asthma in children is about 13 percent of children with hay fever at 16 percent. In 1995 the figures were still at ten and 13 percent. Doctors suspect others as causes of the changes in Eastern Germany higher loads with mite allergens in early life by improved thermal insulation, high temperature stability. by modern central heating and a relative humidity of 60 percent The animals love’s now time warm and humid. Even particles of pollutants such as diesel exhaust, ozone or nitrogen dioxide could be responsible for the increase.
Latex gloves, costume jewelry or jeans buttons, many everyday objects they can cause: contact allergy. Nickel is the main cause of allergic contact dermatitis of the skin. Even professional working in a moist environment encourages the development of many skin eczema. Allergic contact dermatitis is the most common skin diseases in general. According to the Robert Koch Institute in Germany about one in twelve men, and even one woman in five develops sooner or later such a reddish, itchy skin appearance. Most commonly affected are the hands. The number of substances that can trigger an allergic reaction of the immune factors in the skin is almost unmanageable. Approximately 3,000 natural and man-made substances are so far known as a contact allergen. They can meet us in articles of daily life as well as at work, in personal care and even medicines.
But not every contact dermatitis is due to an allergy. A direct, prompt reaction of the skin on contact with chemicals such as a cleaning agent can be expressed in a redness, a slight burning or itching. An acute toxic response to direct damage to the skin caused by irritating or even toxic substances may also exist in a complex cellular inflammatory reaction, which is also reflected as a contact dermatitis. This is also known as irritant contact dermatitis. It is the direct result of a violation of the protective barrier of the skin, in which the immune system also plays a role. The barrier function of the skin affected, pollutants they can penetrate more easily.
During an allergic reaction of the skin, however, the immune system plays the main role. Contact allergy is characterized in that the immune system of the skin cells are hypersensitive to the contact with specific substances react to the organism are harmless. The re-contact with the skin then triggers inflammation. The substance is recognized by the immune system that causes their fight. This reaction is usually an immediately after contact with the substance. It takes one, two or three days, until it is fully formed. In which localization of the lesions is observed depends on where the skin contact was made.
All that is preceded by an unnoticed running sensitization to the allergenic substance – as is the case with all allergic processes.
Another variation of contact dermatitis can occur when regular acting irritants damage the skin always or perpetually out and the repair mechanism of the skin is overloaded. So can slowly develop eczema. All three types of contact dermatitis are different in their external appearance is very similar to and by conventional diagnostic methods such as skin samples barely.
The prevalence of contact allergy in the population is related to the lifetime prevalence is currently around 16 percent. The results in the analysis of the data of the Information Network of Departments of Dermatology (IDU). The IDU collects data for allergic contact dermatitis from 47 clinical allergy departments in Germany, Austria and Switzerland. The lifetime prevalence of the disease incidence in relation to the whole of life. For Central Europe, it is estimated from a frequency of contact allergy between 15 and 20 percent. When contact allergy, it is, therefore, a common disease, and this applies to all age groups. Women are significantly more affected than men. The most common allergens for the IDU-data and data on patch testing are nickel, cobalt, balsam of Peru, fragrance mix, chromium compounds and p-phenylenediamine (PPD).
Currently being discussed in academia, politics and authorities nor on whether an action threshold can be defined, below which no adverse effects are expected. The example nickel shows that thresholds could make perfect sense. Although the nickel allergy is in the ranking of contact allergens is still the undisputed number 1, but the trend for new nickel allergies shows now down. For younger women, a significant reduction in sensitization rates should be noted since the EU has regulated to reduce the concentration of nickel in costume jewelry by law. Also show the data of the IDU. One problem the new, unfortunately nickel-containing euro coins are to be addressed.
In order to predict whether a substance has a high or a low potential to cause allergies, are the research various test methods. Since the late 1960s, the so-called maximization test comes (Magnusson and Kligman) used later came the Buehler test. The latest test is the local lymph node assay (LLNA), which was recognized in 2002 by the OECD as a decision test. With the help of these tests allows identification of the sensitizing potential of these chemicals.
If a person has developed a contact allergy, depends on a variety of internal and external factors, which may be very different individually. To the external factors include the question of how often a person’s skin is exposed to what concentrations of a potential allergen. Another factor is the potential that has a certain substance to provoke skin sensitization: also called sensitization potency. But individual internal factors play a role in a person, does not arise if an allergy or. This includes after all, nobody knows about: gender, age, ethnicity, presence of atopy, other skin diseases, medications, smoking and hereditary factors. However, the exact causes of the exhaustive individually very different awareness readiness are not released until today. Observations of families, twins and even on animals let researchers assume that the genes have an influence on the risk of an individual for an allergy. The science calls the “genetic predisposition for sensitization”. And the infected actually involve: allergies are frequently occurs in families. If a parent or a sibling has an allergy, is the probability that the other child developed an allergy, compared to children of non-allergic increased. Other studies have shown that there are people with an increased sensitivity to multiple sensitizations. Anyone allergic to cobalt is reacted in the epicutaneous (patch test) to the dermatologist more often nickel. A metal allergy (nickel, cobalt, chromium) is more common in people who are already sensitized to other, unrelated allergens. Sensitization to faint fragrance allergens are more common with other fragrance allergies on together. On such potent allergens (like isoeugenol), however, have usually no accompanying allergies.
Although the number of new cases of contact allergy in some allergens, as well as in many professions has been declining for several years, are sensitization and contact dermatitis, including new cases in the population are still widespread. Of the ten “top allergens” sensitization frequency still ranging between 3 and 7 in the case of nickel, even at 16 percent. We have to do so to remain unchanged with a veritable problem. This applies not least to their work. Particularly hairdressers, construction and metal workers and health care workers are also affected today still often of contact allergies. The nickel allergy relates to women in particular. Special scents like oak moss and isoeugenol, a mold made of clove oil are aromatic liquid, not only in private but also in the professional environment eg by masseurs or geriatric nurse (s) relevant. Also rubber allergens such thiurams are of great importance. Epoxy resins may show the problem is larger than previous data. Their diversity was in the testing so far not yet fully taken into account enough. Numerous contact allergy to epoxy resins have been diagnosed not even likely.
For contact allergies in your professional life, it is important to know that the amount and duration of exposure to allergens can arise not only the allergy, but also influenced the severity of the disease. This is also part of the dose-response relationship. Only on this basis can appropriate strategies for prevention can be developed.
Pseudo-allergies are the “real” allergies symptoms very similar, but they are not triggered by immunological mechanisms. Outwardly, the clinical pictures of allergy and pseudo-allergy can not be distinguished from each other. In both the same neurotransmitters are involved in the reaction (eg, histamine). The difference lies only in the mechanism that leads to the release of neurotransmitters. In the “true allergy” the release of neurotransmitters is immune mediated. It is triggered by a specific antigen-antibody reaction to the membrane of the mast cells of the immune system. Unlike the pseudo-allergy: Here the messengers are released by pharmacological mechanisms. The pseudo-allergy is a direct response to certain substances contained in food. It is dependent on a certain dose. There is also no sensitization phase. The effects may occur immediately upon first contact with the substance.
Typical case of pseudo-allergy is the food intolerance, in which the body reacts to most small molecules that occur naturally in foods or these are added as additives. This reaction is, however, the causative agent is not specific. You may, without prior sensitization upon first contact with a substance occur.
Substances that can trigger a pseudo allergy, eg various food additives, preservatives benzoic acid and sorbic acid, histamine (eg, tuna, anchovies), biogenic amines. (eg in yeast extracts, chocolate, avocado, tomato) or salicylates from fruit and wine
The term “allergy” is also used inflationary. Not everything that is called allergy deserves the name. This is contrary to the body’s reaction to allergy-like symptoms. No “true allergies” are in addition to the pseudo-allergy, for example, the sun allergy and food intolerance. The exact role of allergic reactions in atopic dermatitis is also explored. Known also are called intolerances: eg the milk intolerance.
To start the demo movie on the mechanism of contact allergy click here.
The medicine differentiates between different types of allergic reactions. There are allergies with “immediate reaction”. Here are the symptoms in sensitized individuals generally have only a few minutes after contact with the allergen. This is for example the case of hay fever. Allergic reactions to foods such as nuts, celery and shellfish as well as allergies to drugs or insect stings usually follow this pattern.
Allergic contact eczema is different. With him it is an allergy of the “late-type”. Contact point for the allergens, the skin. The symptoms usually only light here 24 to 72 hours after contact with the allergen. After one to three days to show redness, swelling, water blisters, oozing points, scaling and crusting. Typical example of this type of allergy is nickel allergy.
Medical science has also developed a more differentiated classification of the types of allergies. It divides the immunologic-allergic reactions in the types I to IV Airborne allergens and foods dissolve usually a type I reaction (immediate reaction). The symptoms such as runny nose, hives and asthma occurred very rapidly after allergen exposure and are partly seasonal and partly also felt all year. The immune system responds to allergen contact with the release of neurotransmitters such as histamine stored from its mast cells or by cytokines, the inflammatory mediators. In addition, other immune cells that are newly formed (Leukotiene, prostaglandins, etc.) and also released. The person concerned is reflected then around with symptoms of hay fever, or urticaria (hives). Also, food allergies and allergies to insect venoms belong to Type I reaction. Typical of type I is the formation of IgE immunoglobulins of the variety. In the sensitization phase, this particular variety is made of allergen-specific antibodies. These bind to IgE receptors on the surface of certain immune cells called mast cells and basophils. Renewed contact with the allergen, these are interconnected and trigger an inflammatory response.
The formation of a contact dermatitis is a cascade of actions of the immune system in response to an external force acting based substance, in which a limited and the nearest to each other are built.
This contact allergic reaction is immunologically divided into two phases: In the sensitization phase antigens penetrate into the skin (epidermis), where they are bound by the so-called Langerhans cells (LC). LZ also known as antigen presenting cells (APC). Their real job is to intercept pathogens. In antigen presentation endogenous and exogenous molecules (antigens) are loaded on specialized protein complexes and thus made visible to the immune cells. Once an antigen has been bound by such a Langerhans cell, these immune cells travel through the lymphatic vessels to the nearest lymph node. On their way with the Langerhans cells is going on even a change. The immunologist says it matures. This maturation is reflected in the production of different molecules (eg, adhesion), which adhere to the surface of the cell. In certain areas of the lymph nodes yet another variety of immune cells waiting for a task: they are called “naive T cells”. They are the object of the Langerhans cells. LZ present the naive T-cells, the antigen (in so-called MHC-peptide complexes – see below). This leads to the activation of antigen-specific T cells that proliferate and alter the profile of the resulting adhesion molecules by which they eg can bind to the lymph node tissue. In this way they are able to reach across capillaries into the bloodstream and from there specifically migrate into the skin. Messengers (cytokines) call from the Langerhans cells also produce a transformation and expansion of lymphocytes, the intercalate as memory cells in small blood vessels of the skin. Thus the phase of sensitization is complete. They took about eight to 21 days. All this is for the people affected so far passed unnoticed. Symptoms of the disease have not yet been set.
Comes again to skin contact with an antigen (in this case allergen), the second phase of the immune response: the elicitation phase. Now already are antigen-specific T cells present in the skin. They recognize the substance again, which led to the awareness and trigger an immune response further. This is now stronger than in the sensitization phase and finally leads to the formation of the symptoms of contact dermatitis.
It starts with the wall, and thus further expansion of blood vessels, from the granules (“granules”) of the mast cells are messengers (mediators) are released, and white blood cells (neutrophils) is a flow. The granulocytes are actually the defense against infections. They are attracted by bacterial substances or, as here in the allergic reaction of the body’s neurotransmitters and are part of the inflammatory process. Your immune job: They are foreign bodies, bacteria, fungi or destroyed tissue record (phagocytosis). Germs they kill mainly by enzymes located in granules in the formation of hydrogen peroxide. The neutrophils are the most common type of granulocyte (neutrophil response to 70 percent) and have a two-or three-piece / acting-lobed nucleus.
But the granulocytes not stay alone. Attracted by messengers other immune cells enter the picture. These include e.g. Macrophages (scavenger cells, leukocytes), lymphocytes, dendritic cells and two types of T helper cells (CD4 + and CD8 +). They also play in the inflammatory process, which is now visible as a lesion in the skin, an important role. T lymphocytes have the task to destroy foreign cells. Dendritic cells are cells with tree-like cell processes, the Langerhans cells are also included. They are in a position to include lymphocytes and present antigen-antibody complexes. CD4 and CD8 are receptors, molecules on the surface of T-helper cells, whose job it is to detect structures. Monocytes, mast cells and other antigen-specific cells are also attracted by mediators of the inflammation. They destroy nearby tissue and thus also contribute to the inflammatory response, which is produced in the skin as eczema.
The CD4 protein is inserted into the cell membrane of T-helper cells, and protrudes from the surface of the T cell. CD stands for “cluster of differentiation”. Together with the T-cell receptor recognizes CD4 (coreceptor) the MHC class II molecule (MHC = major histocompatibility complex = “major histocompatibility complex”) with the antigen in other body cells. MHC molecules are self-antigens on the surface of every cell in the body. These molecules mark the cell as belonging to the body and regulate immunological processes. They also play a role in graft rejection following transplantation.
CD8 receptor (“cell-toxic”) a recognition molecule of cytotoxic T-killer cells. It is also to a protein in the cell membrane of T-cells. The T-cell receptor recognizes with the CD8 coreceptor as the MHC-I complex on autologous cells. This MHC-I complex is produced by all cells of the body. They show which proteins are produced in a cell. Cytotoxic T cells with CD8 now detect whether they are endogenous peptides, or whether it is a virus peptides or proteins of a cancer cell. They recognize foreign peptides or cancer cells discovered cell is destroyed.
In the event of contact allergy producing CD4 and CD8 T-cell cytokines. This is a group of immune mediators, the various types of substances belong as interferons (IFN) and interleukins (IL). In allergic contact dermatitis excrete the CD8 T cells much more IFN-α (gamma). From (Tz1-cytokine) CD4 T-cells to produce IFN-α either (Th1 cytokine) or IL-10 and IL-4 (Th2 cytokine). While Tz1 cells have an effector function in allergic contact dermatitis – they can not co-stimulation are immunologically active – is the Th1 or Th2 cells awarded a regulatory role: the presence of Th1 cytokines leads to an enhancement of allergic contact dermatitis, weaken during Th2 cytokines it. Messengers of the effector cells lead to immigrate other inflammatory cells and increased leakage of fluid in the intercellular spaces (intercellular edema), to the formation of bubbles in the epidermis.
The allergic contact dermatitis that is is based on an immune response to allergens in the skin, which is mediated by T cells. It is the only cell-mediated response and occurs only with time delay (delayed type allergy, type IV). The symptoms show up three days after exposure to the allergen. Visible and tangible result of these immunological processes is an inflammation in the skin.
In almost all contact allergens are small, fat-loving, chemically reactive molecules or ions alone is too small to trigger a sensitization. To the allergen, they need a carrier protein. They are therefore referred to as “incomplete antigens” or haptens. Because they are small and fat soluble, haptens are capable of penetrating the outer skin layer, the epidermis. It attaches itself to the body’s own peptides (small protein molecules). Upon engagement of the haptens to amino acids or protein structures (peptides, proteins), it can be modified and the whole antigen. The immune cells, they now recognize as ‘foreign’. Metal ions such as nickel directly react with proteins of the MHC class II complex and thus bind to molecules that are associated with the cell membrane.
In contrast to the contact allergy allergic inflammation is triggered in other allergic diseases such as hay fever or of atopic dermatitis by protein antigens.
For sensitization factors such as the concentration of an allergen involved. The contact allergen must be present to induce a sensitization to the skin in a certain minimum concentration. From a certain (high) concentration of the allergen, the ability to raise awareness not be increased. In experiments with the substance of dinitrochlorobenzene (DNCB) showed that the frequency of sensitization was lower, the larger the area of skin was, was applied to the DNCB. DNCB in chemical belongs to the aromatic hydrocarbons.
Consequences of contact allergy
The consequences of contact allergy are often not trivial. Particularly in the vocational sector, the effects are sometimes very extensive. Even lighter, localized symptoms are very unpleasant for those affected and prejudicial. Eczema on hands or feet may result in even to patients at times do not their work. At worst, it might even make a career change is necessary because the only long-term therapy is the healing process leading allergen avoidance. To alleviate the symptoms temporarily come corticosteroids are used.
Composites / sesquiterpene lactone mix – The daisy family (Compositae, Asteraceae) is a plant family with a partially relatively high sensitizing potential. Examples include: arnica, wormwood, yarrow and goldenrod or cultivated plants, such as chrysanthemums, daisies and marigolds. But vegetables such as lettuce and artichokes are among them.
Thiuram mix – shows allergy to gum ingredients. Thiurams be used as accelerators in rubber production (both natural and synthetic rubber). The rubber allergy has as type IV allergy from the latex allergy, a type I allergy, can be distinguished. It occurs mainly in professions (eg health care and construction) or for private activities in which rubber gloves and rubber boots should be worn. May be included in thiurams spray and glue bottles or insect repellents.
(Chlorine) Methylisothiazolinone (MCI / MI) – biocide is effective against bacteria and fungi. Use in cooling lubricants, adhesives, waxes, leather and textiles, (wall) water-based paints, wood preservatives,. In papermaking, in cooling systems as well as in cosmetics and household products such as preserved toilet paper, dishwashing and household cleaning agents or diesel fuel
Propolis – Propolis (also:-kitt, Glue), stuffing, Vorwachs. Resin similar natural product with an aromatic odor. Is produced by bees as adhesives, sealants and Balsamiermasse mainly from the sticky coating of poplar, but also from other tree buds. Propolis may contain more than 180 compounds in varying, and regionally varying concentrations.
Turpentine oils – essential oils from the resin of conifers (Pinusarten). Solvents or diluents in paints and coatings, in shoe polishes, floor cleaning products, and resins in building materials, in broncholytic and antirheumatic agents as well as insecticides. For turpentine were cross allergies e.g. described to tea tree oil.
Epoxy – a group of plastic prepolymers. Their use has been increasing for about 50 years. Use primarily in the professional sector (eg construction, crafts) also plays in the DIY sector a role.
Nickel is for years and still the undisputed top allergen. In Germany, an estimated 1.9 to 4.5 million people have a nickel allergy. About 16 percent of tested patients (age-and sex-standardized) sensitized to nickel sulfate. Allergies to this common metal are usually triggered by nickel-containing jewelry, such as earrings or piercings, ear clips, rings or necklaces. The sensitization is often held at an early age. Small “fake” necklaces and earrings are for little girls and many mothers alike.
Sooner were the buckles of garters and corset and fake ear plugs cause of nickel allergies, since the 1990s until today, the ‘body-piercing’ new ways of raising nickel sulfate opened. Nickel may also be present in countless everyday objects. In (fashion) jewelery, eyeglasses and watches, as well as in various fasteners on clothing such as buttons or zippers and hooks and buckles for shoes in Also in the kitchen nickel is present, for example in cookware, cutlery and kitchen utensils. And utility and housing items such as scissors, keys and door knobs can be sources of nickel. Even in silver and white gold as well as coins can be contained significant amounts of nickel. Metal alloys can be found in up to 20 percent nickel.
Nickel allergy sufferers must even be careful with certain foods. Nickel is found in cocoa, chocolate, soy, oats, shellfish, legumes (eg, beans), cashew nuts and black tea. But also in earth and hazelnuts, sunflower seeds and licorice can be contained nickel. The shell of all cereals contain nickel. Canned foods can also be nickel.
One bright spot is the trend in women aged under 40 years. Here are suggested in recent years to a slightly weakening trend of nickel sensitization. Between 1992 and 2001 the rates of nickel sensitization were in the youngest age group (30 years or younger) from 28.0 to 17.5 percent (significant). In older age groups, they showed a slight but significant upward trend. For men, the trends are similar, but at a lower level. Even in young men were and are popular piercings. In the age group of men under 30 from 1992 to 2001 the rates of nickel sensitization went from 8.9 to 5.2 percent (significant). This decrease is most likely due to decreased exposure to nickel costume jewelry (piercing), although no evidence that piercing had lost itself attractive.
Since the early 1990s, there are nickel-containing products for exposure limits. Otherwise, the product initially had the note “is nickeliferous” bear. Later, in 1996, the sale of products exceeding the limit was forbidden. In ear plugs nickel is prohibited.
Well as occupational allergen nickel plays a role, eg with tailors, tavern keepers, musicians or cashiers. In the professional area, one hand plays the contact to nickel-containing alloys or nickel-plated objects a role (workpieces, tools). On the other occurs, contact with solutions of nickel salts, such as in the manufacture of batteries, the surface treatment of metals or grease and plastic processing (catalysts). Other nickel-risk occupations are the production of pigments (eg, ceramics) and printing inks, the finishing of textiles, electronics and magnet production. Nickel is also a component of insecticides and fertilizers.
A common source of nickel is also smoking: cigarette tobacco also contains nickel, which merges with up to 20 percent in the smoke.
An ingredient found in henna tattoos can cause allergic reactions the way. The allergist watching with growing concern. The background: The “Body Painting” is becoming more and more popular. Increasingly, so dermatologists report, patients come to the doctor’s offices because they are allergic to hair dyes, textiles or a henna tattoo. The awareness has mostly taken place in the most beautiful weeks of the year: the holidays. On the streets and beaches of southern countries offer artists the coveted gift, the delicate black henna tattoos on. So the henna color is darker and more intense, her para-phenylenediamine (PPD) is added. The substance has a strong sensitizing potential, so that it can come from renewed contact with PPD to allergic contact dermatitis. The Federal Institute for Risk Assessment (BfR) in Berlin thus warns against the risks associated with body painting.
Although para-phenylenediamine may be used in cosmetic compositions for Europe of the skin can not be added. But in cosmetics use in hair dyes is allowed under European law. “A layman sees a body painting color but does not indicate whether it contains the sensitizing PPD”, says BfR President Professor Dr. Dr. Andreas Hensel and advises travelers precaution to refrain from henna tattoos. Henna itself no sensitizing effect has been demonstrated. In cosmetic use on the skin, it is not yet approved in Europe.
Those who have sensitized to PPD can lifelong allergy to the substance or to colors with a similar chemical structure. Products containing these substances must be avoided consistently. And that’s not so easy: Para-phenylenediamine can happen except in hair dyes as part of dyes in dark leather and dark fabrics. Particularly tragic is a PPD allergy for hairdressers, printers, footwear and leather goods seller and workers in the textile, rubber and chemicals industry. You often need to change their jobs. For young people who are allergic to PPD, these professions remain closed.
Cause and effect
The amount and duration of exposure to allergens with determining whether or not forming an allergy. It’s called the “dose-response” relationship. And it also determines the severity of the disease. Therefore, in modern cosmetics ingredients are used in reduced concentrations that are below the established or accepted threshold for an allergy.
There are estimates that 1.4 to 3.4 million people are sensitized to fragrance ingredients. But cosmetics are sometimes also wrongly discredited as a cause of contact allergy. Many of the 26 fragrances that have been classified by the EU as declarable, have been found at Epikutantestreihen as relatively unproblematic. The awareness rates were very low. Often found on the sensitization in cosmetics contained ingredients not by the cosmetics themselves, but from other sources instead.
In terms of commonly used cosmetic preservatives in the evaluation of patch testing, for example, for some relatively high sensitization rates result (methyldibromoglutaronitrile / phenoxyethanol), for others (biocides, MCI / MI, formaldehyde, parabens) are not. Possible explanation: The sensitization to these substances are not likely primarily caused by cosmetics, but by medical skin medicines (at parabens) or through professional contact with biocides (MCI / MI and formaldehyde).
The contact dermatitis is an inflammatory reaction of the skin, which is characterized by symptoms such as redness, swelling, blistering, oozing, papules, scaling or dryness of certain skin areas. The term “eczema” is from the Greek and “flare up” means. The patient has a “healthy” by the itching feeling his skin would. Responsible for these unpleasant skin symptoms are usually outwardly acting, harmful factors that may cause any infection, yet elicit an immune response, or those that cause direct damage to the skin. You can have very different origins of chemical or physical nature. Even natural substances may be responsible for contact dermatitis. The contact allergic reaction is usually one of the so-called delayed-type (usually type IV, rarely possibly Type I). Of allergic contact dermatitis, also known as irritant contact dermatitis, allergic to the product is different from the reaction of the immune system to a concrete acting outside specific allergen. This allergic reaction is always preceded by a sensitization.
The contact dermatitis can vary greatly in appearance. Numerous external and internal factors affecting the individual inflammatory response of the skin and can look very different. Exogenous factors play a role, such as: type, concentration or solubility of the substance, and the body temperature, pressure, cold, UV light, water and climate conditions, etc. However, the sensitivity of the individual concerned, a specific sensitization, existing atopy skin diseases, the age, or a sensitivity to UV light may affect the inflammatory response of the skin.
As an “example” for contact dermatitis contact dermatitis is often described. The lightest acute form is a redness of the skin at the site of exposure to a substance, possibly with slight swelling. It can form bubbles, which in severe forms filled with clear liquid, burst, can soak violently and eventually dry up. Later forms a crust that ultimately abschuppt and releases the skin completely healed. Because the symptoms often associated with more or less intense itching, additional damage caused by scratching the skin. Allergic dermatitis is formed from only 24 to 72 hours after exposure to the allergen and usually heals back completely.
The acute form of contact dermatitis can be chronic. The skin then heals from no longer complete, limiting the plaques is blurred, the skin thickens and the skin texture is coarser. A feature for the distinction of acute irritant contact dermatitis from chronic degenerative – the two are not necessarily allergic variants – is the time to onset of symptoms after the skin has been exposed to the substance. The acute irritant contact dermatitis develops very quickly, within minutes to hours after exposure. Symptom is often a painful burning and appearance is often very intensive up to the death of skin cells and tissue areas.
The chronic degenerative form stamped out until much later, sometimes after years. After chronic damage certain parts of the skin, for example, by constant contact with water, soap or solvents of fat and acid mantle of the skin is damaged. Cracks occur in the epidermis, by both pathogens and allergenic substances acting can easily penetrate the skin. In constant contact with potential allergens may thus develop an allergy. Chronic Konkaktekzeme have against acute a slightly different appearance: The initial inflammatory reaction develops back to the herd but tend to inflammatory skin thickening, strong cornification, gross scaling and coarsening of the skin condition. The folds of skin characterize off. This degenerative contact eczema is dry and cracked, it peels, the course is slow and it also heals only slowly. Commonly affected are between fingers and backs of hands. Both forms of eczema, the irritative acute and chronic degenerative are mostly restricted relatively clear. Allergic contact eczema however, tends to scatter. Allergens are also transported via the lymphatics and blood vessels, so that it can come in places to allergic skin reactions, which are not directly come into contact with the allergen.
A special form of contact dermatitis is the “diffuse contact dermatitis’: it is triggered by allergens that are spread through the air. These include dust (cement, sawdust / wood fiber, dry parts of plants or tea), but also fragrances (essential oils, sprays, fumes or perfumes). Diffuse contact dermatitis often the face is affected.
For dermatologists, it is to distinguish the forms of contact dermatitis described also by other symptoms and diseases. The lesions can be colonized by bacteria or fungi, or more rarely by viruses. In these cases, of course, must be treated differently. It is an underlying atopy detect and possible light sensitivity, which can lead to eczema photoallergic uncover. Allergic reactions to over the air-borne allergens (such as plant allergens) and a volatile chemical (such as epoxies) applies in the workplace, it decrypt. The dermatologist also contact dermatitis from the borders of some diseases with similar appearance as the seborrheic dermatitis and psoriasis. This is so important because the necessary therapies are partly strongly differ from the contact dermatitis.
Atopic dermatitis, of which are particularly common children and young adults affected is also called atopic dermatitis or atopic dermatitis. About the exact causes that medical science knows too little, when they could be treated causally. It is known that she has hereditary backgrounds. There are familial tendencies to develop an atopic disease. These include allergic rhinitis, allergic asthma and atopic eczema. In the skin of atopic dermatitis, the protective barrier is disturbed to external influences. The skin is extremely dry. An additional itching often leads to scratching and pulling damages the skin by itself. The skin reacts concerned about shooting in a variety of environmental stimuli that are tolerated by normal skin problems. Atopic dermatitis is not necessarily an allergy, but it can have an allergic component. Often the units to the allergic individual are poorly informed, for example, in relation to suspected food allergies (eg milk). On the other hand, the parties have often very high IgE levels to environmental allergens in the blood and often concomitant allergic diseases such as hay fever and allergic asthma. Evidence that certain allergens in atopic eczema play a part to be replaced in some of the cases by the so-called “atopy patch test”. The tendency to develop an allergy is greater in one than in the case in any event atopics Nichtatopikern. People with eczema should avoid if possible professions in which a greater risk of sensitization, it was. By dealing with allergenic substances or by an increased burden on the skin, such as the frequent work in wet environments Studies show that sufferers have a higher risk for development of allergic occupational diseases and usually sooner and harder than Nichtatopiker ill.
Non-allergic contact reactions
Not all types of contact dermatitis are as mentioned above due to allergic reactions. A eczema can also be the direct result of the action of an irritant or corrosive substance, such as the skin contact with chemicals. The reaction occurs in the skin such irritants on the very first contact. The more of such an irritating substance with the skin comes into contact, the greater the response.
For the diagnosis of the skin doctor first examines the eczema itself: your typical morphological appearance and the location where they occurred, give important clues to the causes. Eczema on wrists, neck, ear lobes or the umbilical region, for example, point to nickel or cobalt from costume jewelry or metal knobs as the cause. The patient has symptoms in the face, the dermatologist will ask for the application of ointments, creams, eye drops and contact lens solutions. For the physician, it is also important when the eczema has occurred. An eczema formation with a time lag of about two to four days after exposure to a substance indicates an allergy of the delayed type. Even after the occupation, the examiner will ask you to come to a possible Berufsdermatose on the track.
So are the first evidence available, can be deliberately sought. Now comes the so-called patch test (also called “Läppchentest” or “patch test”) are used. With its help skin reactions to individual substances are detected. Here, the substances in question are in dilute solutions applied to these patches and stuck to the skin on the back. After a day or two can be read first skin reactions. After another two days, then the end result is clear. Are typical eczema originated, then the epicutaneous sensitization of the patient has been diagnosed with the drugs, the self-identified as an allergen. Due to the temporal evolution of the symptoms, the doctor may suggest an type IV allergy (delayed).
Before each patch testing by a trained physician must allergologically anamnesis (case history) and raised the skin condition to undergo a test capability. Requested information to atopy, occupation and possible allergen contacts. According to the data of the patient then the test program is compiled. The test solutions should be tested galenically (galenically: the preparation of a drug on, composition of ingredients, dosage form) and approved as a drug allergen preparations are used.
What helps if the skin is irritated and inflamed?
The most important therapeutic measure against contact dermatitis is strict avoidance of the causative agent and the allergen. Immunotherapy, as it is performed in inhalation allergies, is not yet established for contact allergies. However, it is not always possible to completely eliminate the substance in question from the personal environment of the patient, or the contact with an allergen to avoid completely. In these cases, appropriate measures must be taken to protect the skin. That, in the case of hand eczema, for example, protective gloves. Support is the protection by a care concept as at work, if feasible, through customized technical work arrangements. Employers and workers can / should explore whether it is possible to change work processes to avoid wet work or use, for example, suction devices. Gloves should not be worn for more than each required for the skin to breathe again and can dry off by eventual perspiration.
Make oozing eczema be treated with wet compresses and water-containing ointments, chronically dry changes with fatty creams. If it came to a very severe contact dermatitis with marked symptoms, the temporary use of medically prescribed ointments or creams are needed. In the short term, for example, containing cortisone preparations are used.
In the treatment of the symptoms of contact dermatitis depending Ekzemart come several albums as well as other drug therapies used. The top priority in the acute form of this inflammatory skin disease safely corticosteroids. The chronic eczema dermatologists may also move with ultraviolet rays (UVB and PUVA) at bay. Germs are in the game, in addition antiseptics are used. Calcineurin inhibitors are in Germany, Austria and Switzerland are not approved for the treatment of contact dermatitis. Following the acute treatment, they are still used in the medical therapy of freedom occasionally, some probably with considerable success. In order to speed up recovery and prevent re-formation of eczema, a concomitant or subsequent treatment with moisturizing creams makes sense. The important thing is the skin care products precisely tailored to the individual needs and condition of the skin. Improper care can sometimes do more harm than good. In very severe, chronic or refractory cases, the treating physician could also bring systemic therapies, ie syringes or steroid tablets, used. The itching is alleviated in part with antihistamines.
Current research is directed towards substances to intervene at different points in the allergic inflammatory process and may be selectively introduced into the skin. Further therapeutic trials such as a so-called T-cell vaccination or desensitization about taking drops or tablets with allergens are not transcended in the contact allergy on the experimental stage. A previously purely theoretical approach is the treatment of dendritic cells in vitro with an immune factor IL-10 and subsequent restoration to the patient’s body.
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