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Prevalence of allergic rhinitis for last century grew in tens of times. In the developed countries from 10 to 30% of people have allergic rhinitis.
Rhinitis happens intermittent (seasonal), persistent (year-round) and professional (also not the allergic nature is possible) allergic rhinitis. Depending on expressiveness of clinical manifestations allocate the following forms of a disease:
• easy: there are only insignificant clinical manifestations which are not interrupting day activity and/or a sleep, the patient realizes existence of displays of a disease, but can do also without treatment;
• medium-weight: symptoms of rhinitis interrupt a sleep, interfere with work, to study, sports activities, quality of life significantly worsens;
• heavy: symptoms are so expressed that the patient cannot normally work, study, play sports or leisure during the day and to sleep at night if does not receive treatment.
Etiology and pathogeny
The major factors causing emergence of symptoms of allergic rhinitis are the allergens which are contained in air which can be divided into three groups:
• aeroallergens of external environment (pollen of plants);
• aeroallergens of dwellings (mites of house dust, animals, insects, mold, some house plants);
• professional allergens.
In addition, allocate the following starting factors which lead to development of nonspecific nasal hyperreactivity (hypersensitivity to various nonspecific influences) and can provoke development of a disease or promote its aggravation:
• cold influence;
• spicy food;
• emotional loadings;
• stressful situations.
The pathogeny of allergic rhinitis is a classical example of the IgE-mediated allergic reaction of the first type which consists of two phases.
In an early phase of the allergic answer the mast cells bearing specific
IgE, migrate in a mucous membrane of a nose and distinguish the allergens which got there. Linkng of a mast cell with allergen immediately causes its activation and degranulation. At the same time in intercellular substance inflammation mediators from which main thing is the histamine are allocated. Influencing walls of vessels, mediators increase their permeability that causes hypostasis of fabrics and a rhinorrhea. They also stimulate secretion of glands and expand an arteriovenous anastomosis (throttle veins) that increases a krovenapolneniye of cavernous fabric, the sizes of nasal sinks also are caused by difficulty of nasal breath. The histamine irritates the terminations of esodic nerves of a mucous membrane that causes a burning sensation and reflex attacks of sneezing. In an early phase symptoms of rhinitis appear already several minutes later after contact with allergen.
In several hours after permission of an early phase, even without repeated contact with allergen, there is a delayed or late phase of the allergic answer which is characterized by secondary increase of maintenance of a histamine and other mediators of an inflammation, and also increase in quantity of eosinophils and basophiles in a mucous membrane of a nasal cavity. The T lymphocytes of the 2nd type which are activated at interaction about antigen-prezentiruyushchimi cells participate only in a final phase of a pathogeny of allergic rhinitis (their accumulation requires quite long interval of time). Their cytokines (mainly to SILT-5) participate in maintenance of a fabric eosinophilia.
The natural course of allergic rhinitis significantly differs from the sequence of the events which are taking place after single provocation described above. Repeated influences of the same concentration of allergen cause more expressed clinical symptoms. This phenomenon called praymiruyushchy effect is that influence of allergen prepares a mucous membrane for the subsequent contacts, doing it more sensitive. As a result at each subsequent provocation the quantity of pollen particles which is required for emergence of symptoms of rhinitis decreases in tens of times. Also the fact that persons, sensibilizirovanny to pollen of trees and meadow herbs, after the end of a season of blossoming respond with the expressed rhinitis symptoms even to the minimum concentration of pollen of herbs in air is explained by it.
At persistent (year-round) rhinitis when long influence of low concentration of allergen takes place, the chronic inflammation in a mucous membrane of a nose develops. It is proved that at patients with any form of allergic rhinitis, even for lack of repeated influences of allergen for a long time, inflammatory changes — "the minimum persistent inflammation" for a variety of reasons remain.
At a pathogeny of allergic rhinitis there is also a neurogenic component of an inflammation which is shown at release of neuropeptids from the terminations of cholinergic and peptidergichesky neurons.
At patients with allergic rhinitis constitutional features, change of sensitivity of receptors to mediators and the irritating incentives, reduction of the threshold of reflex reactions, and also vascular and microcirculator changes can be the cornerstone of nonspecific hyperreactivity of a mucous membrane of a nose.
Clinical signs and symptoms
Treat the main symptoms of allergic rhinitis:
• difficulty of nasal breath;
• allocations from a nose (rhinorrhea);
• burning (itch) in a nasal cavity;
• pristupoobrazny sneezing.
Less often patients are disturbed by decrease in sense of smell, a headache, displays of conjunctivitis, a febricula and a sleep disorder.
Features of a clinical picture of the main forms of allergic rhinitis are provided in the table.
The diagnosis and the recommended clinical trials
When collecting the anamnesis it is possible to establish connection of emergence of symptoms with certain allergens. Of a pollen allergy it is characteristic:
• combination of allergic rhinitis and conjunctivitis;
• seasonality of aggravations (emergence of symptoms of an illness in the spring, in the flying and in the early fall — in a blooming period of plants);
• meteodependence (deterioration in health of patients in dry windy weather when the best conditions for pollen distribution are created);
• a cross food sensitization (approximately in 40%) and intolerance of some phytodrugs.
At a household allergy are typical:
• effect of elimination (reduction or disappearance of symptoms of allergic rhinitis outdoors (at the dacha, in business trip, on issue);
• aggravations in a crude season (in the fall, in the winter, in the early spring);
• strengthening of symptoms in the first half of night;
• emergence of symptoms during the cleaning of the apartment, knocking-out of carpets, viewing of old books and papers.
For an allergy to hair of animals
it is characteristic:
• emergence of symptoms at contact with animals and carrying clothes from wool and fur;
• intolerance of the HP containing proteins of animals (heterological serums, immunoglobulins, etc.).
At a fungal allergy are noted:
• intolerance of the products containing yeast (beer, kvass, dry wines, fermented milk products);
• an aggravation of symptoms in wet weather, at visit of the crude, badly aired rooms;
• seasonal or year-round disease with deterioration in the spring, in the flying and in an early autumn;
• existence of the centers of a fungal infection.
External displays of allergic rhinitis are poor. The slightly opened mouth, dark circles under eyes (because of a staz in periorbital veins as a result of constantly broken nasal breath), puffiness and a dermahemia of wings of a nose and over an upper lip (attract attention at plentiful allocations from a nose). At the persons forced because of an itch it is constant to rub a nose tip, on skin of a ridge of the nose the cross fold is formed. At children this usual gesture is called "allergic salute". Especially at a seasonal allergy, also displays of conjunctivitis are quite typical.
At a front rinoskopiya and endoscopic research hypostasis of nasal sinks, gray or cyanochroic color and characteristic spottiness of a mucous membrane (Voyachek's symptom), and at the time of an aggravation — a significant amount white, sometimes a foamy secret in the nasal courses come to light. At the long-term anamnesis of persistent allergic rhinitis polypostural changes of a mucous membrane, usually in the field of the average nasal course, a hypertrophy and polypostural regeneration of the back ends of the lower nasal sinks are observed. Test with Epinephrinum shows reversibility of the revealed changes. It is necessary to pay attention to anomalies of an anatomic structure of a nasal cavity, especially acute thorns and crests of a partition of a nose." Piercing" in a mucous membrane of an opposite nasal sink, they strengthen and support the hypostasis which is available already and expressiveness of clinical manifestations, reduce efficiency of drug treatment and, besides, can be a source of the pathological rino-bronchial reflex leading to development of a bronchospasm.
• The general blood test (the eosinophilia is typical).
• More specific method is the microscopy of the smear separated from a nasal cavity, painted by Romanovsky's method. At allergic rhinitis the maintenance of eosinophils is increased and makes more than 10% of total quantity of cells.
Allergy diagnostic tests. For identification of causal allergens use skin tests. Usually use tests by a prick (prik-test). For this purpose the set of allergens is applied on forearm skin, then pierce with a fine needle skin in the place of their drawing and through certain time measure the sizes of a skin blister. Along with allergens apply test and control liquid (negative control) and 0,01% histamine solution (positive control). The immediate allergic reaction developing after contact with allergen is shown by Levis's triad: a blister, a hyperemia and a skin itch which are most expressed in 10 — 20 min. after putting allergen. Results of the prik-test estimate at necessary terms, measuring the sizes of skin papules and comparing them to positive test control.
Scarifying tests are more sensitive, but are less specific and more often give false positive reactions.
Intracutaneous tests put only at disputable results of prik-tests, and also in need of allergometrichesky titration.
For specification of the clinical importance of allergen (in addition to comparison to clinic of a disease) use the intranasal provocative test. It will be out only with those allergens on which positive skin reactions were received. For statement of the test enter 2 — 3 drops of the distilled water into one half of a nose and then the increasing cultivations of the tested allergen: 1:100, 1:10 and whole solution. The test is considered positive if in 20 minutes after administration of allergen there is a rhinorrhea, sneezing, burning and a congestion of a nose. The positive intranasal test confirms that this allergen really causes rhinitis symptoms. For more exact assessment of test results in dynamics conduct endoscopic research of a nasal cavity, a front active rinomanome-triya or collect a nasal secret for cytologic research.
Both skin tests, and the intranasal provocative test in rare instances can cause a bronchospasm and heavy allergic reactions, in particular, in patients from the accompanying bronchial asthma therefore have to be carried out only by the trained personnel in a special office. Use of only serially let out standardized extracts of the allergens allowed for use in Russia is admissible.
Indications for determination of concentration of the general and allergen - specific IgE are:
• difficult for interpretation and doubtful results of skin test;
• existence of typical clinical manifestations at negative skin test with this allergen;
• false-negative skin reactions owing to reception of antiallergic HP at impossibility of their cancellation;
• impossibility of statement of skin tests.
Level of the general IgE is close to zero at the time of the birth, but in process of a growing gradually increases. After achievement of 20-year age levels over 100 — 150 PIECES/l are considered as raised.
Determination of concentration allergen - specific antibodies can be carried out radioallergosorbent (most widespread), radio immune, immunoenzymatic or hemolyuminestsentny by methods. Methods of quantitative definition of IgE have specificity about 90%, can be carried out even in the presence of the accompanying skin displays of an allergy, the concomitant use of antihistaminic and glucocorticoid medicines does not affect their result. Wide use of these methods is still limited to their high cost.
In most cases diagnosis of allergic rhinitis does not cause difficulty because of accurate communication of emergence of symptoms with a certain allergen. In some cases it is necessary to carry out differential diagnosis of allergic rhinitis with other diseases, one of symptoms of which is the rhinorrhea. In particular, at children aged from two till four years differential diagnosis of allergic rhinitis and recurrent virus respiratory infections still represents considerable difficulties.