Description urticaria
Hives or urticaria is a very common disease that affects at least once in their life 20-30% of the human population. By definition, urticaria disease characterized by planting called. Buds (wheals or urticaria), which are generally itchy, and which are completely healed (doctors indicate this status as healing ad integrum). Hives frequently suffers young adults.
Causes and mechanism of urticaria
Although urticaria itself may cause a number of causes, we can say that all these hives are accompanied by a common factor, and that is the degranulation of mast cells.
Mast cells or mast cells are special cells which are found throughout the body, and which are often located in close proximity to blood vessels. These cells are produced and stored in their granules many active substances or agents that during degranulation, a process of releasing these substances out of the cell, they get into the body and blood, and can specifically operate. Mast cells are highly specialized cells that have a very wide apparatus substances synthesized: eg .: histamine, prostaglandin D, leukotriene C, leukotriene B, heparin, chondroitin sulfate E, interleukins, which represents an IL of IL-3, IL-4, IL-5, IL-6, IL-8, IL-13, as well as tumor necrosis factor etc.
All of these substances have in the body’s physiological functions, which are also very numerous, but in brief it can be said that mast cells are involved in the development and maintenance of inflammation. Inflammation is substantially uniform and stereotyped response of the organism to a pollutant, in order to eliminate this pollutant. Furthermore, mast cells may play a role in immunological reactions affect local blood circulation etc.
The fact that mast cells are capable to locally influence the circulation, it is very important for an explanation of the characteristic changes in the skin. Many substances which are released upon degranulation of mast cells, act as vasodilators vessels (vasodilatation in which thus flows more blood).
This results in two things, and that is when hives appear first skin redness and consequently characteristic wheals. When the vasodilatation of blood vessels is that locally increase the amount of blood that flows into the area. Simply put, more red blood in the cause reddening of the skin – doctors talking about the so-called. Erythema.
With vasodilation and also thanks to further increases působkům another important factor –vascular permeability (permeability of the vascular wall to water and the substance contained therein). Liquid gets into the corium (dermis, the second layer of skin beneath the epidermis), wherein the top of each extruded masses of cells, giving rise characteristic výsevům that his skin patient sees.
We now know that symptoms of hives are caused by mast cell degranulation. What is important is what one degranulation causes. Generally we can say that the mechanisms are several. These mechanisms degranulation can then be seen as a fundamental cause of urticaria. For clarity, the mechanisms of mast cell degranulation and therefore mechanisms of hives are divided into three basic groups: immunological and non-immunological idiopathic.
immunological mechanisms
These mechanisms are also several types, the first one is the possibility of immunopathological reactions of type I according to Gell and Coombs. In 1963 Gell and Coombs divided faulty immunological reactions into 4 groups, and one of them, namely type I, is first possible mechanism urticaria.
This immunopathological reaction assumes the presence of an allergen (i.e. the antigen, often proteinaceous substance to which the body alergické- very simplified). At this allergen to bind antibodies of type E, which after binding to the allergen are capable by changing its spatial conformation, which is caused by binding to an allergen to bind to receptors on mast cells and give a signal to degranulation. This whole concept is very simplistic.
From the foregoing that the key factor to degranulation (at least in terms of immunological mechanisms) is a connection-type antibodies to E receptor which is on the surface of mast cells.Coupling of the antibody with the receptor produces a signal which is transmitted in the cell where further generate signals that lead to degranulation. At this point it should be reiterated that, degranulation occurs only if a connection alergen- antibody-receptor.
For an explanation of the immunological mechanisms of urticaria whole thing must still somewhat complicate claiming that there are cases where in the body resulting antibodies that bind to receptors on mast cells or produced antibodies which are directed against antibodies of type E. To these two cases actually occurs . These antibodies, which are directed against receptors of mast cells (ie cell body’s own) and anti-antibodies (also formed body), are necessarily harmful character since break down the regulation of body functions. Such antibodies, called autoantibodies(meaning directed against your own body). Binding of these antibodies can in turn lead to degranulation.
non-immunological mechanisms
These mechanisms are also very colorful. There are substances which can directly induce the degranulation of mast cells: codeine, contrast agents. In addition, however, there are many substances that can trigger degranulation indirectly, often through unknown mechanisms: they are certain preservatives, angiotensin converting enzyme inhibitors, NSAIDs etc.
Inflammatory mechanisms
This term covers a wide range of cases where the cause of degranulation and urticaria not known.
Signs and symptoms of urticaria
The basis of the disease is the formation of wheals. Pomfus is very itchy, swollen, flat and well defined bearing. Wheals arise very quickly (within minutes) and also quickly disappear (usually within one day of their creation, which does not preclude the creation of new wheals). Wheals can vary widely in terms of their size. They may have a size that the eye hardly perceived by the after emergence mapovitých surfaces (this is known as urticaria gigantea or geographica).
Another difference can cause pressure on wheals and production fluids, which may be above the clinical appearance change of the form of blistering (to form the blisters, the condition is known as urticaria vesiculosa, urticaria bullosa). The contents of blisters may be clear or hazy blood (then of course we are talking about hemorrhagica urticaria).
The most obvious symptom is itching for a patient who is usually very intense. Itching raises tended to friction, not to scratch the skin. Therefore, excoriation (skin damage when nails scratching) is not a typical symptom. Itching is most intense in the formation of buds, then it is milder in the evening.
These basic symptoms of the disease may be accompanied by symptoms scarce: it is mainly the possibility of damage to the mucous membranes, which is reflected difficult breathing, hoarseness and diarrhea. Furthermore, they can develop swelling and pain in the joints, the patient may have a temperature, it can feel like malaise.
Dermatologists distribute many types of urticaria. According to localization, causes like.
Physical urticaria are retrieved, as the name suggests, physical influences. They are relatively common and account for approximately 20% of all urticaria. An example might be:
cholinergic urticaria
It is caused by increased body temperature (through physical exertion, sweating, overheating, stress, etc.). The cholinergic urticaria manifests penetration of symmetrical sowing numerous smaller wheals. Such wheals can coincide with each other and thus create a larger bearing. In this type of swelling may occur, and the patient may have impaired respiration (but this is rare). The patients are mainly young adults and distances himself. See urticaria participates in the activation of the sympathetic autonomic nerves, which innervate glands in the skin.
symptomatic dermographism
Symptomatic dermographism or urticaria factitia rash, which occurs after the skin hard blunt object writing. These symptoms disappear within 15 minutes.
Urticaria Mechanica tarda
This occurs for about 2-6 hours after application of pressure perpendicular to the skin and appears as a painful swelling, to which may be added sickness (nausea), fever, myalgia, arthralgia.
cold urticaria
Cold urticaria is triggered by skin contact with cold air or water. On itchy skin formed buds.
solar urticaria
Solar urticaria arises after exposure to ultraviolet radiation to the exposed skin, which causes seed strongly pruritic buds but which disappears within 20 minutes.
Localized heat urticaria
Localized heat urticaria is a very rare, buds arise again after skin exposure to higher temperatures
Akvagenní hives
Akvagenní urticaria formed after contact with water, wherein the factors are likely irritating substances dissolved in water. Sometimes akvagenní urticaria accompanied by a variety of blood diseases.
contact urticaria
Contact urticaria is characterized by formation of the skin upon contact with a substance that has the ability to induce urticaria (immunological or non-immunological mechanismem- see above).
Diagnose hives can mostly be of clinical findings, however, no cause of hives is a very difficult task even for an experienced doctor. The differential diagnosis should be considered the possibility urticaria- vasculitis syndrome.
Wheals (similar to the classic hives) are triggered by leukocytoclastic vasculitis of postcapillary venules (vasculitis is an inflammation of the small vessels, in this case postcapillary venules, ie the smallest possible veins that connect to capillaries). When inflammation occurs disintegration of white blood cells (white blood cells during inflammation migrate into tissues, where they are lured by chemical mediators – this phenomenon is referred to as chemotaxis). White blood cells disintegrate, they release their products, which damage blood vessels, which adheres to the nuclear prach- leukocytoklazie.
Clinically manifest this syndrome that wheals painful rather than itchy, and further by wheals on the skin occur more than 24 hours. As a result of vascular damage occurs to the skin to a so-called.Purpurám – large areas composed of tečkovitých bleeding into the skin.
acute urticaria
The patient we see almost daily sowing wheals, this form of urticaria heals within 6 weeks.
Acute intermittent urticaria
Sowing wheals formed, alternately appear on the skin and stay there for longer than 6 weeks
chronic urticaria
This urticaria is defined as a disease with urtikálními sowings continuous or recurrent least 2 × weekly for more than 6 weeks. This rash may last for decades. In half of the cases fail to determine the cause.
treatment of urticaria
Since the exact cause of hives is not known, accessing frequently used to treat the symptoms nemoci- known. Symptomatic treatment. An integral part of symptomatic treatments, the introduction of general measures to eliminate any risk or worsening factors reduce excessive heat, stress, alcohol, tight underwear.
It is also recommended for some types of urticaria apply lukewarm showers, wear good clothes to replace a group of drugs substances that impair the hives. For the last measure it is necessary to say that compensation can take place only if the replacement drugs maybe.
Local treatment is focused on suppressing itching, which is the worst for the patient. Suitable is the application of solutions and ointments, containing 1% menthol. A very important aspect of treatment is to inform the patient that despite the complicated investigation and search for the cause of the disease is the reason for its creation are often unexplained.
The overall treatment is directed primarily to the administration of antihistamines (sedating antihistamine combinations and sedating). Then there is the administration of tricyclicantidepressants (amitriptyline, doxepin, etc.). Administration of corticosteroids may be applied to control acute sowing. When inception to anaphylactic shock is a life-saving procedure byadrenaline.
How can I help myself
Adherence to treatment guidelines and general recommendations.
complications of urticaria
Development of anaphylactic shock, which is connected inter alia with a massive edema of the larynx, which prevents the respiration, and the patient will suffocate.
Other names: urticaria, wheals, cholinergic urticaria, symptomatic dermographism, Mechanic tarda urticaria, cold urticaria, solar urticaria, local heat urticaria, akvagenní urticaria, contact urticaria, acute urticaria, acute intermittent urticaria, chronic urticaria