Allergic dermatitis are a group of chronic allergic diseases that manifest as itchy rashes on the skin. Pathology occurs under the influence of food, household, medicinal or industrial allergens. Symptoms of allergodermatosis: hyperemia, edema, itching, polymorphic rash on the skin, lichenification and peeling during the long course of the disease. Allergy tests, immunological, clinical and biochemical blood tests, a coprogram, and a study for dysbiosis are prescribed for diagnosis. Treatment includes antihistamines, corticosteroids, stabilizers of mast cell membranes, supplemented with local therapy in the form of ointments, lotions.
Allergic dermatitis are one of the most common pathologies on the globe, which is diagnosed in 5-7% of the adult population. According to WHO, the true prevalence of skin allergies reaches 25-33%. A higher incidence rate among residents of developed countries. The problem is of great medical and social importance, since the polyvalent sensitization of the population is constantly increasing, respectively, the frequency of skin allergoses and other allergic diseases is increasing.
Causes of allergodematosis
Skin allergy is a multifactorial disease with a complex mechanism of development that occurs when a combination of negative effects of exogenous triggers, functional changes in the body, various pathologies, burdened heredity. The causes of allergic dermatoses can be grouped into the following groups:
- Nutritional factors. Food is the most common allergen that causes skin allergosis. This is due to both hyperreactions to the usual proteins of food, and the frequent use of preservatives, dyes, flavors in finished products. Most allergy sufferers have cross-sensitization to several food antigens.
- Gastrointestinal diseases. Gastroenterological diseases are associated with an increased risk of allergies, because with digestive disorders, changes in the microflora, antigen proteins enter the body. They cause repeated sensitization, provoke relapses of allergodermatosis.
- Unfavorable microclimate of the premises. The main danger of residential buildings is called dust mites of the species Dermatophagoides pteronyssinus, Dermatophagoides farinae. The waste products of these insects become a trigger for up to 50-80% of exacerbations of allergic dermatitis, therefore allergy to household dust is recognized by WHO as a “worldwide health problem”.
- Uncontrolled medication intake. Due to the large number of over-the-counter medications, the availability of medical information, people prefer to self-medicate, taking medications for a long time without indications. Dietary supplements with an unknown composition, which are not subject to certification, also pose a great danger.
- Hereditary predisposition. Genetic mutations cause changes in the barrier function of the skin and innate hyperreactivity of the immune system to antigens, infectious agents. In this case, the first manifestations of allergoses occur in childhood, continuing throughout life.
- Occupational hazards. The risk group consists of workers who are constantly in contact with chemical allergens — doctors, chemists, builders, hairdressers, makeup artists. They are more susceptible to the development of contact dermatitis, eczema, and the risk is directly proportional to the length of work.
- Industrialization of countries. Industrial emissions, exhaust gases, an abundance of cosmetics, household chemicals, a large number of goods made of synthetic materials — all these triggers, with constant contact, provoke the appearance of chronic allergic pathologies.
The main immunopathological mechanism is a change in the ratio between the fractions of Th-helper cells Th-1 and Th-2 in favor of the latter, resulting in increased production of proinflammatory cytokines, specific immunoglobulins E (IgE). Immunoglobulins are fixed on the membranes of mast cells, provoking the release of allergy mediators (histamine, kinins, serotonin), which are responsible for the development of typical external manifestations of allergodermatosis.
With skin allergies, inflammation is chronic, since there are memory T cells. They remain in the skin, settling on Langerhans cells, keratinocytes, and maintain the constant activation of immunopathological mechanisms. In turn, mechanical skin irritation causes damage to keratinocytes, the release of mediators of an allergic reaction, which in the literature is called the “itchy-comb cycle”.
The hypothesis of “hygiene” is widely spread among scientists, which explains the frequent occurrence of allergodermatosis among residents of countries with a high level of development. Experts explain that the widespread use of antibiotics and vaccines targets the immune system to recognize and perceive initially harmless factors (for example, some products) like toxins. As a result, hyperactivation of immunity occurs, clinical signs of pathology appear.
Symptoms of allergic dermatitis
Skin allergies include several diseases, the main of which are: atopic dermatitis, allergic contact dermatitis, eczema, urticaria. Also, various forms of allergic vasculitis, toxicoderma, herpetiform dermatitis of During belong to this group. Along the course, all allergopathologies have acute and chronic stages, periods of exacerbation, remission. An increase in symptoms is observed in the autumn-spring period.
Acute symptoms are represented by redness, swelling of the skin, nodular (papules) and vesicular rashes (vesicles). A characteristic feature of all types of allergoses is a strong itching of the skin, which causes discomfort to the patient, causes psychoemotional disorders, disrupts performance, sleep. Against the background of combs, erosions, weeping, healing with the formation of crusts are usually formed.
In the chronic course of allergic dermatitis, patients are concerned about periodic itching, excessive dryness, peeling, thickening of the skin, strengthening of its pattern (lichenification). In typical places of rashes, there are areas of increased pigmentation. A specific sign of chronic allergoses is “polished nails” with worn edges that occur during daily skin combing.
Due to constant scratching with allergic dermatitis, the barrier properties of the skin are violated, contributing to the attachment of a secondary bacterial or mycotic infection. Pustular rashes (pyoderma) are the most common complication, which, with massive spread over the surface of the body, disrupts the general condition of patients, causes a rise in body temperature, malaise.
Chronic allergoses are usually associated with herpetic infection of the skin, mucous membranes. If the elements of the rash are localized on the face, the disease is complicated by conjunctivitis, blepharitis. Up to 80% of patients suffer from respiratory allergies, and about 30% eventually develop bronchial asthma. In addition, noticeable elements on the surface of the skin, severe itching force a person to limit social activity, can provoke depression.
Allergic dermatitis have a typical clinical picture, so a dermatologist makes a preliminary diagnosis during a physical examination, dermatoscopy. Further examination is carried out together with an allergist-immunologist to confirm the immunological nature of the disease, to identify provoking factors. The diagnostic plan includes:
- Immunological tests. To determine the cause of allergodermatosis, the results of a study of specific IgE antibodies to the most common antigens are required. According to the indications, an extended analysis is carried out with the determination of fractions of T-lymphocytes and B-lymphocytes, other immunoglobulins (IgA, IgM, IgG).
- Allergy tests. Prick tests are the “gold standard” of diagnostics, with the help of which triggers are detected in a particular patient. Allergy tests are performed only during remission, standard allergens are used for their formulation: pollen, household, epidermal, medicinal.
- Blood testing. Clinical and biochemical analyses are important for assessing the general condition of the body, the functioning of internal organs, and the exclusion of concomitant diseases. Be sure to determine the level of blood sugar on an empty stomach, if there are deviations in the results, a glucose tolerance test is recommended.
- Stool analysis. Given the frequent association of allergic dermatitis with dysbiosis, other gastrointestinal pathologies, the specialist prescribes a coprogram, a study of feces on eggs of worms, protozoa. Valuable information is provided by the analysis for dysbiosis, the results of which reveal the predominance of pathogenic flora in the intestine.
A patient with allergodermatosis requires consultations with other specialized specialists: a dentist – to detect caries as the main chronic focus of infection, a gastroenterologist – in the presence of deviations in the coprogram and / or complaints from the gastrointestinal tract, an ENT doctor – with a high degree of colonization of the oropharynx by conditionally pathogenic microflora.
Treatment of allergic dermatitis
Allergic dermatoses require long-term complex treatment, which includes not only pathogenetic, symptomatic medications, but also lifestyle and nutrition correction, elimination of concomitant pathology, and the fight against complications. Patients are selected an individual hypoallergenic diet, it is recommended to remove dust-retaining items from the house as much as possible. When allergodermatosis is associated with professional triggers, it is necessary to change jobs.
Pathogenetically justified direction of treatment is the use of antihistamines. Medications inhibit the molecular reactions underlying allergic inflammation, block the release of proinflammatory mediators, which quickly relieve subjective symptoms, reduce skin symptoms. In addition to H1-histamine blockers, allergodermatosis therapy uses:
- Glucocorticoids. Systemic steroids are used in short courses with severe exacerbations of allergic dermatitis, widespread skin lesions. They are often supplemented with cell membrane stabilizers, which inhibit the main links in the pathogenesis of allergosis.
- Tranquilizers. Medications are indicated during exacerbations with unbearable itching, which interferes with sleep, daily activity of the patient. In addition to tranquilizers, herbal sedatives, hypnotics, and antidepressants are used.
- Probiotics. Preparations with beneficial bacteria are necessary for the elimination of dysbiosis. For greater efficiency, they are combined with prebiotics, digestive enzymes. In the acute period of skin allergosis, sorbents are prescribed to eliminate antigens.
- Antibiotics. Antimicrobial therapy is required when allergodermatosis is complicated by pyoderma, as well as for the rehabilitation of chronic infectious foci – triggers of exacerbation of skin allergosis. In case of recurrent pustular rashes, immunomodulators are also recommended.
With allergic dermatitis, local therapy is necessarily carried out. The most effective are ointments with topical steroids, antihistamines, which quickly eliminate the skin manifestations of the disease, relieve itching. At the stage of wetness and ulcers, lotions with antiseptics and anti-inflammatory compounds are effective. Phototherapy (UFO) is used as an auxiliary method.
Prognosis and prevention
With the exclusion of contact with the allergen and complex drug therapy, recovery occurs, but with repeated interaction with the trigger, the disorder worsens again. Allergic dermatitis are characterized by a wave-like chronic course, so the prognosis for full recovery is doubtful. The combination of skin manifestations with other allergic diseases is alarming.
Primary prevention of allergic dermatitis involves the maximum exclusion of risk factors: proper nutrition, regular wet cleaning of premises, reasonable controlled prescription of medications. The basis of secondary prevention is the avoidance of contact with antigens, and if it is impossible to do this, preventive administration of antiallergic drugs during periods of the most likely exacerbations (autumn, spring).