Dermatitis

Dermatitis is an inflammation of the skin, often allergic. Caused by various agents: chemical, physical, etc.

Dermatitis is the most common pathology of the skin. Due to the constant impact on it of various environmental factors both in everyday life and in the conditions of large-scale industrial production and agriculture. In the general structure of dermatological pathology leading to temporary loss of ability to work, dermatitis is from 37 to 65%. Differing in the degree of severity and the reasons for their development.

New chemical compounds, synthetic materials, hydrocarbons, as well as various production factors lead to a worsening of the situation, contribute to a sharp increase in dermatitis, especially of allergic nature.

Dermatitis is an inflammatory skin reaction that occurs in response to the action of exogenous irritants of physical, chemical and biological nature.

[1], [2], [3], [4], [5], [6]

Causes of dermatitis

Most dermatitis is based on delayed-type hypersensitivity, that is, inflammatory foci appear on the immune basis involving the microcirculatory bed and the complex biomorphological, tissue and cellular processes developing in this zone.

Factors affecting the skin from the outside, in their etiology are divided into physical, chemical and biological. By the nature of the impact, they are divided into:

• unconditional (obligate), capable of causing dermatitis with a certain strength and duration of exposure in each person (mechanical damage, high temperature and other physical factors, concentrated acids and alkalis).
• conditional (facultative), causing dermatitis only in persons with increased sensitivity to them (washing and washing-up liquids, turpentine, nickel salts, formalin, chromium compounds, dinitrochlorobenzene, furacilin, rivanol, etc.).

Dermatitis arising under the influence of unconditioned stimuli, called simple, artificially, artificial dermatitis, which arise under the influence of conditioned stimuli-sensitizers, are called allergic.

Dermatitis is acute and chronic.

[7], [8], [9], [10]

Pathogenetic mechanisms of dermatitis

1. With the development of simple contact dermatitis arising in response to the action of unconditional (obligate) stimuli, the leading role is played by the strength and duration of the damaging factor. A consequence of this can be a significant area and depth of skin lesions. Individual reactivity of the skin in this case plays only an auxiliary role, contributing to a more rapid or slow restoration of the integrity of the skin or the abatement of the inflammatory reaction (age characteristics of the body, the individual ability of the skin to regenerate)
2. In the development of allergic dermatitis due to skin contact with exoallergens (sensitizers, polymers, synthetic resins, low-molecular substances of plant origin, drugs - antibiotics, sulfonamides, rivanol, furacilia, novocaine, etc.), skin sensitization occurs, that is, an increase in sensitivity to this allergen. In the process of sensitization, an immunological response is formed in the form of the formation of specific antibodies or sensitized lymphocytes. A significant role in the formation of the primary immune response is played by Langerhans cells (white process epidermocytes).

In the development of the disease, the state of the epidermal barrier is of great importance, being in a complex dependence on the activity of the nervous, endocrine and immune system. Allergic dermatitis, which appears as a manifestation of delayed-type hypersensitivity, arises from the ability of all kinds of contact allergens to bind to skin proteins.

The main stages of dermatitis

Risk factors that promote the development of simple contact dermatitis, especially in production conditions, are non-compliance with safety regulations and violation of working conditions that lead to damage to exposed skin areas. The degree of inflammatory reaction is directly dependent on the strength and duration of the effect of the damaging factor.

The development of allergic dermatitis is mainly promoted by poorly conducted professional selection, which did not take into account the presence in the past of persons engaged in this or that branch of industry or agriculture, allergic diseases, and then - peculiarities of working conditions (non-observance of production technology) and everyday life (sensitization by household allergens). In addition, the presence of chronic diseases that change the reactivity of the body in general and the skin in particular, also contributes to the development of allergic dermatitis.

Pathomorphology of dermatitis

With all clinical forms of dermatitis, epidermis and dermis are involved in the process. The histological pattern is rarely specific, which makes diagnosis difficult, but the predominance of one or another component of inflammation can serve as a starting point for determining the type of dermatitis. In acute dermatitis due to severe disorders in the microcirculatory bed, accompanied by severe violations of the permeability of the walls of the vessels, the exudative component appears to the fore. In the upper parts of the dermis, there is a sharp widening of the capillaries, edema and mononuclear, mostly perivascular infiltrates. In the epidermis, due to sharp edema, as a rule, bubbles and vesicles are found, pronounced spongiosis, intracellular edema near the blisters. Strengthening the edema leads to reticular dystrophy of the epidermis and an increase in the number of blisters. Fusing, they form large, multi-chambered bubbles that contain serous exudate with an admixture of mononuclears at the beginning and neutrophilic granulocytes in the subsequent periods of the disease. In the stratum corneum may be a crust.

In the histological picture of subacute dermatitis, spongiosis, intracellular edema, and the presence of epidermal blisters are common, usually of small size and located in distinct epidermal segments between edematous cells. In the future, as a result of proliferation of epidermocytes around the blisters, they seem to advance into the upper layers of the epidermis, located in the upper parts of the germ layer. Sometimes acanthosis and parakeratosis are observed. Inflammatory infiltration in the dermis is similar in composition to that of acute dermatitis, edema and vascular reaction are somewhat reduced.

With chronic dermatitis, moderate acanthosis is observed with lengthening of the epidermal outgrowths, hyperkeratosis with parakeratosis, small spongios, but without vesicles. Inflammatory infiltrates are localized mainly perivascular in the upper parts of the dermis, their cellular composition is the same as in subacute dermatitis; exocytosis, as a rule, is absent. The vessels are somewhat enlarged, the number of capillaries is increased, there is a proliferation of collagen fibers in the upper parts of the dermis, including papillae.

Symptoms of dermatitis

Simple contact dermatitis is characterized by the following symptoms:

1. Clarity of the boundaries of the lesion, more often in open areas, corresponding to the boundaries of the impact of the damaging factor.
2. Response inflammatory reaction of the skin, corresponding to the strength and duration of the impact of the damaging factor and manifested by monomorphic eruptions, in connection with which the staging is traced during the process:
   • erythematous stage, characterized by inflammatory hyperemia and edema;
   • Bullous-vesicular stage - the emergence of intense blisters, vesicles filled with serous, less often serous-hemorrhagic contents;
   • ulcerative-necrotic stage - the formation of necrosis areas followed by ulceration and scarring, leading to gross deformations of the skin.
3. Upon the termination of contact with the damaging factor, inflammatory changes are resolved depending on the depth of the lesion and the ability of the patient's skin to regenerate (the age preceding the disease state of the skin).

Allergic dermatitis occurs in sensitized patients and is characterized by the following symptoms.

1. Lack of clarity of the borders of the lesion, with a possible spread to the areas adjacent to the contact zone, especially involving the surrounding skin folds;
2. The polymorphism of the eruptions (true and false), which does not allow us to identify the staging associated with the force of the allergy-affecting factor, but arises with an acuity due to the degree of sensitization. Eruptions are often represented by areas of soft erythema, against which are located papular, vesicular and vesicle elements. Perhaps the emergence of drip wetness, with the further drying of serous exudate and the formation of small layered crusts, creating a picture of peeling.
3. Upon the termination of contact with the allergen, the inflammatory effects on the skin may subside, but in rare cases may increase, depending on the degree of sensitization. In the future, in the absence of qualified medical care, with the unspecified nature of the allergen, the transition of the acute course of the disease into a chronic one, with further transformation into an eczematous process, is possible.

The course of dermatitis is divided into acute, subacute and chronic. The clinical picture is characterized by polymorphism of rashes. The range of manifestations can range from limited edematous erythema to severe bladder and even necrotic changes, generalized erythematous, erythematous-nodular, papuleveziculosis and vesiculitis, accompanied by itching of varying degrees. Allergic dermatitis can often recur, causing infiltrates in foci of lesions, which are often eczematoid in nature and serve as a breeding ground for eczema.

Differential diagnosis of dermatitis

Diagnosis of simple dermatitis usually does not cause difficulties, but one should remember about possible self-harming of the skin (patemymia) by persons with unstable psyche.

Allergic dermatitis should be differentiated from eczema, which is characterized by more persistent current, prevalence and polyvalent sensitization, pronounced evolutionary polymorphism (microvesicles, microerosions, microcapsules). In addition, it should be remembered about the development of professionally conditioned allergic dermatitis, requiring confirmation of the pathologist

Indications for hospitalization of the patient are the vastness of the skin lesions, expressed subjective sensations (itching, pain), a clinical picture represented by vesicle-bullous elements, foci of necrosis.

[11], [12], [13], [14], [15], [16]

Treatment of dermatitis

With simple contact dermatitis, symptomatic treatment is indicated. In the stage of erythema, lotions (1-2% solution of tannin, boric acid, 0.25% solution of silver nitrate) or short-term steroid ointments (celostoderm, prednidolone, sinaflan) are used. In the stage of vesiculation and the formation of blisters, wet-wiping dressings with the above solutions. Then, after opening the blisters, the erosive surfaces are treated with an aqueous solution of aniline dyes (1-2% solution of brilliant green, methylene blue, Kacellani liquid), followed by lubrication of the skin with epithelializing ointments (5% methyluracil ointment, solcoseryi colpid cream).

In the stage of necrosis, surgical excision or the appointment of leading enzymes (trypsin, chemotripsin) in the form of lotions, followed by the use of epithelializing agents.

For the treatment of allergic dermatitis, patients in the first stages need the appointment of desensitizing agents (antihistamines, calcium preparations) in combination with external methods of treatment (5% dermatol emulsion, lanolin emulsion zinc ointment, 3% naphthalene paste, colpid cream).