Description allergies
The human immune system is used for recognition and disposal of foreign and potentially harmful elements (molecules, microbes, parasites or larger inanimate particles). If immunity is properly “set” is a very effective protection against countless diseases.
But it may be that the immune system responds inappropriately and those environmental factors that harmful to humans. These reactions are manifestations of hypersensitivity (hypersensitivity) and belong to the group. Immunopathological reactions.
Hypersensitivity manifested by specific symptoms known asallergy as the cause of the allergen. Allergen always comes from the external environment. If the pathological immune response directed against parts of her body, then we talk about autoimmune diseases, which are described elsewhere.
Allergy symptoms can either take the form of barely noticeable, or they can greatly annoy the patient to be life threatening. It depends on how strongly the allergy developed what way and in what quantity the body allergen enters. It is virtually impossible to list here all potential allergens. They are generally pollen, dust, mites, bacteria, mold, and substances contained in food and pharmaceuticals, as well as the protein consisting of stinging insects and animal poisons.
What happens in the body?
The creation of an allergic reaction, the immune system to foreign particles first understand and decide on its harmfulness. This decision is crucial, since the particles will never be an ordinary particle, but always allergen. The emergence of hypersensitivity to this particle is calledsensitization and the entire process takes about three weeks.
The particle is first ingested large immune cells (macrophages) that it decomposes and then on its surface “exposed” fragments. This event on another cell (helper T lymphocytes) that communicate with macrophages, and then send the event information to the cells at a stationary end of the process (B-lymphocytes). B-cells undergo a change and after a short time will make antibodies (IgE).
The antibodies are constructed such that at one end having the structure corresponding to the shape of the fragment of the original particle. In the future, if the body enters into the same particles, the antibody will be able to establish their surface. Its other end with antibody early after its formation either bind to the surface of the so-called. Basophils, immune cells circulating in blood or to the surface of mast cells, similarly equipped with elements performing immune surveillance in the mucous membranes and skin.
New meetings with the particle, now allergen, leading to anaphylactic reactions. When the allergen is bound to the IgE antibody and the binding information is immediately transferred to the interior of basophils and mast cells, which are responding blasts quantities of active substances into the environment. These compounds, which include e.g. histamine, heparin, prostaglandins etc., then dilate blood vessels, allowing penetration of fluids from the blood into the surrounding tissue (edema formation), blood clotting and causes contraction of visceral organs.
According to the mode of entry of the allergen into the body then creating local reactions (in the mucous membranes of the respiratory and gastrointestinal tract, on the skin) or total (allergen was injected into the blood stream, which is circulated and responses are apparent even at distant sites from the point of entry). Specific symptoms are listed below.
Risk Factors Allergies
The actual cause of the failure of the immune system leading to allergic reactions is not yet precisely known. Allergy is a disease with a multifactorial basis, this means that at its origin has multiple different factors.
Perhaps the most important factor is genetic predisposition. A genetic predisposition to develop allergies is called atopy. If one of the parents of a child atopic (without, however, there had allergies occur during life), a child has about a 30% chance allergies. If both parents are atopic, the probability rises to 60-80%. For this reason, so far it seems unlikely that one could somehow prevent the development of allergy.
Outside the genetic disposition as other factors are likely to apply: industrial air pollution, ozone, cigarette smoke, and also raising living standards and health care (limited contact with the natural impurities in nature, vaccinations etc.). It is proven that families whose members come from a young age in contact with animals and soil and drinking water from natural sources, allergies suffer a statistically lower number of cases.
Many allergies through prolonged and excessive exposure to certain substances eg. In the work environment. Perhaps only those you protect, but the choice of occupation according to the probability of professional allergy is certainly not normal procedure.
Some form of allergy suffering today more than a fifth of the population. The development of symptoms usually occurs in childhood (often already in infants). Later they are discovered allergies to substances with which the person rarely encounters a lifetime (the first contact is followed by sensitization of the second contact is usually associated with allergic reactions), as is the case with some drugs, exotic foods, insect bites, and the like.
The best prevention in these cases it is next allergen avoided and where it can not, it is necessary for each case equipped with drugs which alleviate the reaction.
Signs and symptoms of allergy
Symptoms can be divided according to the routes of entry into the body allergic to an allergen.
In case of inhalation (inhalation) eg. Pollen allergies from the environment reports watery runny nose and sneezing. Chronic condition is referred to as hay fever (pollinosis). Serious manifestation of asthma (asthma), a set of symptoms including shortness of breath mainly because of the withdrawal muscle of the bronchioles (difficulties are especially exhalation, which is sometimes accompanied by an audible whistling) and the urge to cough.
Aeroallergen also irritate the auxiliary equipment of the eye, leading to excessive tearing, splitting eye and conjunctivitis.
When ingested allergens, allergy may manifest mucosal swelling in full contact with the bite digestive tract. There is thus a possibility of swelling root of the tongue with obstruction of the airways. Among the manifestations of food allergy also include nausea or vomiting, crampy abdominal pain, diarrhea, and later may appear rash.
When an allergen enters directly into the bloodstream (eg. Insect bites), symptoms may take overall character (and very fast). These include swelling, download organs consisting of smooth muscles (respiratory, abdominal organs) presenting with dyspnea and spastic abdominal pain,itching and / or a rash.
Severe reactions are reductions in blood pressure due to enlargement of the lumen of blood vessels (vasodilation of hypotension). Activation of the regulatory mechanisms of the body is then reflected as a rapid heart beat (tachycardia). Skin is noticeably pale with the touch sticky, cold sweat. The latter symptoms are consistent with a condition called anaphylactic shock, which directly threatens the life. If the apparent development of these symptoms (especially an overall feeling of itching, nausea, abdominal pain beginning, quickened heartbeat) eg. By insect stings, do not hesitate to calling emergency services.
Atopic dermatitis is a skin allergic inflammation. While hay fever and asthma are manifested in preschool and younger school children, eczema can be seen already in infants. It is a dry, scaly,pale red districts, occurring in small children on the face and neck, then the elderly in the folds of the skin (knee and my elbow, armpits, toes). Eczema typically itchy, leading to a danger of intrusion rozškrábání and microbes.
investigations allergies
Family doctor suspects allergy with the typical symptoms that plague patients. Sends it to a specialist, allergist, who will initially focus on identifying the allergen.
Forearm are patient during an examination Subcutaneous commercially manufactured diluted allergens. After about half an hour to evaluate the skin reaction to a specific allergen (redness and pale bud at the site represent a positive finding).
Allergists also bled and asks laboratory for determination of antibody levels (particularly IgE). They can provide information about the severity of allergies. If the patient has difficulty breathing, is also performed spirometry. The knowledge gained is then a springboard to determine the optimum treatment.
treatment of allergies
Treatment usually involves administering antihistamines, mostly seasonally (according to the occurrence of allergens in the air). In the case of respiratory distress they are prescribed drug in the form of an aerosol or a powder for inhalation. They are applied either regularly or as a reliever medication only for troubleshooting.
Corticosteroids are drugs having immunosuppressive, it means that attenuate the immune response. This effect however is not their main effect (the others include e.g. affect the metabolism of water and salts, the effect on blood pressure, etc.), So the long-term administration by inhalation or tablets is not desirable. But they are preferably applied topically in ointments for the treatment of eczema.
In recent years, increasingly relies on the so-called therapy. Desensitization. The organism is for a time of incorporation of the allergens by injection starts at very small concentrations and over time the concentration increases. The body thus antigen “habit” and after successful treatment it already may not respond at all.
The disadvantage of treatment is uncertain outcome at a relatively high cost and the need for regular commuting to the clinic for the injection. The patient must always be for a few tens of minutes after application to remain under medical supervision, if there is no allergic reactions.
In case of allergy to the drug (usually allergies such as iodine disinfectants, penicillin etc.) it is in the patient’s best interest to this fact in time to inform the medical staff, with which will come within the treatment administered into contact. For such a patient are used with other active drugs or supportive components, but the same effect.
Food allergy requires avoid in the future any dishes that may contain allergens.
Allergy sufferers, for which in the past showed severe reactions to anaphylactic shock (typically after insect bites) are equipped with standby package containing mostly antihistamine,corticosteroid, and probably also inject epinephrine (EpiPen auto-injector), which can be allergic if needed to apply himself. A severe allergy should also inform their relatives, which can inject this.In the case of children, it is imperative to inform about serious allergies teacher or head of the children’s collective in whose care the child is handed over.
How do I help myself
If possible, an allergy sufferer could contact with the allergen should be avoided. The doctor may advise you to purchase various aids for people with allergies (eg. A hypoallergenic linens, etc.), Where the market is enough and nowadays no longer affordable. At home, it is advisable to use a vacuum with a HEPA filter. The basis of success in the fight against allergies discipline and adherence to the treatment prescribed by a doctor.
complications allergies
The most common complication is a logical worsening symptoms of untreated allergies. For example, the original intermittent fever varies in chronic rhinitis and asthma in the end.
Chronic irritation of mucous membranes may lead to the microscopic eye and visible changes.Among those visible changes include the usual pseudo tumors, eg. Nasal polyps.
Furthermore, the cold can turn into chronic inflammation, conjunctivitis, sinusitis or even otitis media. Unless previously present atopic eczema and then he can develop as a complication.
Anaphylactic shock is the most serious complication requiring immediate professional intervention with the administration of epinephrine, antihistamines, corticosteroids and infusion fluids. It is described elsewhere in this server.
Other names: hypersensitivity, hypersensitivity, atopy, anaphylaxis
