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Morphological elements of skin rashes

 
, medical expert
Last reviewed: 19.10.2021
 
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When evaluating the affected skin, first of all, the morphology of the rashes is established, their prevalence or limitation, localization, symmetry, asymmetry or linearity (for example, along the nerve or vessel) are analyzed, the features of the mutual arrangement (scattered, grouped, draining). Monomorphism or polymorphism (true and evolutionary) of rashes is defined. When diagnosing dermatoses, palpation of rashes, their scraping, pressing on the surface with glass (vitrection, or diascopy) and other additional methods of investigation are used.

For any character of the location, a change in the skin should be carefully analyzed morphological elements of the skin rash - first primary, then secondary.

Primary called vysypnye elements that arose on previously unchanged skin.

Secondary vysypnye elements arise as a result of the evolution of primary.

In dermatology, there are six additional pathological conditions of the skin that, in a number of diseases, appear on previously unchanged skin, and in a number of others they are the result of the evolution of other elements of skin rashes.

When examining dermatological patients, it is possible to identify 23 morphological elements. The primary vysypnye elements include stain, blister, nodule, tubercle, knot, vesicle, bladder, abscess.

A macula is a change in the color of a patch of skin or mucous membrane without changing its relief.

Spots are divided into vascular, pigmented and artificial.

Vascular spots have different shades of red. Their pathomorphological basis is unstable or persistent vasodilation, excessive formation of the latter and the release of blood from the vessels. Stiff vascular spots reflect a reflex vascular or inflammatory response. In the course of vitrification, they disappear completely (hyperemic spots). Small (up to 2 cm in diameter) vascular spots are called "roseola", larger ones - "erythema". Persistent vascular spots are caused by the paretic dilated vessels due to the restructuring of the microcirculatory bed (telangiectasia) or excess neoplasm of the vessels (hemangiomas). In cosmetology quite often use the term "couperose", which means persistent telangiectatic erythema. Vascular spots that arise as a result of the release of blood cells from the vessels into the tissue per rhexin or per diapedesim, are called hemorrhagic. Fresh spots have a cyanotic-violet color and do not change during vitrection. Over time, their color changes to brownish-yellow due to oxidation of hemoglobin (oxyhemoglobin - reduced hemoglobin - biliverdin - bilirubin). Hemorrhagic eruptions have a special name - "purpura" (it can appear on the skin with petechiae, vibice, and ecchymosis).

Pigmented spots are associated with excessive content of pigment melanin (hyperpigmented spots) or, conversely, inadequate content (absence) (hypopigmented and depigmented spots).

Artificial spots are formed when external dyes are injected into the skin, usually various dyes (tattoo, permanent make-up and art.) Or as a result of the deposition of some coloring metabolic products (eg, carotenoderma) in the skin.

Blister (urtica) - itchy, above the level of the skin, itchy, frostless formation of white or reddish white with a smooth surface, a dense consistency and a short time. The urticar element exists from a few minutes to several hours (up to 24 hours) and is allowed without a trace. The mechanism of the formation of the blister is the localized edema of the papillary layer of the dermis, which arises from the sharply developing expansion and simultaneous enhancement of the permeability of the vessels, upon exposure to a number of biologically active substances (histamine, serotonin, acetylcholine, etc.). It is most common in hives and reflects an allergic reaction of a reactive or immunocomplex type. In the case of diffuse edema of the subcutaneous tissue, a giant blister (angioedema, or Quincke's edema) appears.

Uzelok, papula (papula), - rising above the level of the skin, is the formation of a different density, inflammatory or non-inflammatory origin.

Papules can be formed as a result of proliferation in the epidermis (acanthosis, hypergranulosis), infiltration in the dermis (lymphocytes, histiocytes, mast cells, etc.), the proliferation of various structures in the dermis (vessels, secretory divisions and excretory ducts of glands, etc.) metabolism (lipids, mucin, amyloid, calcium, etc.).

Papules are inflammatory and non-inflammatory. Nodules that reflect the inflammatory process are colored in various shades of red. Non-inflammatory elements may have the color of normal skin or be pigmented. In the form of distinguish flat (epidermal and epidermodermal), hemispherical (dermal) and pointed (follicular) papules.

In size papules are distinguished: miliary (with the size of a millet grain - up to 2 mm in diameter), lenticular (about the size of lentils - about 5-7 mm in diameter), nummular (about the size of a coin - about 2-3 cm in diameter) and plaques (5 cm and more in diameter).

Tuberculum (tuberculum) is a limited inferior member from 2 to 7 mm in diameter, which rises as a result of the formation of a chronic inflammatory infiltrate (granuloma) in the dermis. The mechanism of the formation of the tubercle is a productive granulomatous inflammation in the dermis. It occurs with some rare dermatoses (tuberculosis, tertiary syphilis, leprosy, sarcoidosis, etc.). In the opening, the tubercle is very similar to the inflammatory papule. Color varies from reddish-brown to cyanotic red, the consistency is dense or soft. Bumps tend to occur on limited areas of the skin, grouped and can merge. Unlike the papule, the tubercle always leaves a scar (after ulceration.) Or cicatricial atrophy (without ulceration) at its resolution.

Nodule (nodus) is a large, bespostnoe formation of various densities, inflammatory or non-inflammatory in nature, located in the subcutaneous adipose tissue and in the deep layers of the dermis.

Nodules can be inflammatory and non-inflammatory. Inflammatory nodes are colored red in various shades. Can rise above the skin or settle in its thickness. Nodes that reflect acute inflammation have fuzzy contours, a dough-like consistency (for example, a furuncle). In contrast, nodes that present chronic inflammation or a tumor differ in varying degrees of density, with clear boundaries. Nodes, which are a clinical reflection of specific inflammation (for tuberculosis, tertiary syphilis - gum, leprosy, sarcoidosis) or malignant tumor, may undergo disintegration

Veslcula (veslcula) is an uplifting cavity formation in the epidermis, ranging from 1 to 5-10 mm, containing a serous fluid.

The cavity in the formation of the bubble is always intra-epidermal, sometimes multi-chambered. The mechanisms of vesicle formation are vacuolar dystrophy (intracellular edema), spongiosis (intercellular edema), ballooning dystrophy (a sign of epithelial cell damage by herpes viruses).

Bubble (bulla, pemphig) is an uplifting cavity formation larger than 10 mm, containing a serous or serous hemorrhagic fluid.

The shape and size of the bladder may be different, the cavity is one-chamber. The cavity can be located intraepidermalmo (subcorneally and suprabazalno) and subepidermally. The cavity of the bladder occurs only if the epidermis cells are pre-damaged, the bonds between them or between the epidermis and the dermis are broken. The causes of these injuries can be exogenous and endogenous. Exogenous include obligate physical factors (friction, high temperature), as well as chemical factors (obligate concentrations of acids and alkalis) and biological nature (microbes). Endogenous factors are immune complexes that exert an immunopathological effect on the desmosomes of the epidermocytes (acantholysis in pemphigus), the basal membrane (epidermolysis with bullous pemphigoid) or the connective tissue of the tips of the papillae (Dühring's dermatosis).

Pustula (pustula) is a cavitary uplifting formation, measuring from 1 to 10 mm, containing pus.

The pustule always represents a cavity inside the epidermis, sometimes below it. This primary cavitary efflorescence element is formed as a result of necrosis of epidermal cells with the formation of a purulent cavity. The formation of pustules is preceded by damage to keratinocytes by the products of the life activity of pyogenic microbes (exogenous factors of infectious nature) and enzymes of neutrophilic granulocytes. With some dermatoses, the formation of pustules is due to the action of sufficiently studied endogenous factors of non-infectious nature, called "amicrobial pustular dermatoses."

It should also be emphasized that after the establishment of the type of primary element of the rash for the verification of the diagnosis of dermatosis, histological examination of the skin is of great importance.

The secondary morphological elements of skin rashes include a secondary stain, erosion, ulcers, scar, scales, crusts, fissures, abrasions. Their significance for retrospective diagnostics of dermatoses is not the same.

A secondary spot (macula) is a local discoloration of the skin on the site of former rashes.

The secondary spot can be hyperpigmented, which is more often caused by the deposition of hemosiderin and less often - melanin, and hypopigmented due to a decrease in the amount of melanin due to a temporary disruption of the function of melanocytes found in the area of the pathological focus.

Erosion (erosio) - a superficial defect of the skin within the epidermis.

Erosion occurs more often as a result of the opening of the intraepidermal cavity, less often due to a disturbance in the trophism of the epidermis due to the pathological process in the dermis (for example, erosive syphilloma). Erosive defect is epithelialized completely without scar formation.

Ulcer (ulcus) - a deep defect of the dermis or underlying tissues.

The ulcer occurs due to the disintegration of pathologically altered foci of purulent-necrotic inflammation, ischemia (trophic ulcer), infectious granuloma, malignant tumor (this is different from the wound that arises from the exogenous violation of the integrity of the layers of the skin). With the evolution of the place of ulcers, a scar is formed, which often repeats it in its form.

Cicatrix is a newly formed connective tissue in place of damaged skin and deeper tissues.

There is no skin pattern in the scar area, note a decrease in the number or absence of hair. There are normotrophic, hypertrophic, atrophic and keloid scars. Normotrophic scar is located at the level of the skin, hypertrophic - protrudes above it, atrophic - is below the skin level. Keloid scars are classified as pathological scars, they protrude above the skin level and are characterized by active peripheral growth, especially after their excision, and subjective sensations (itching, paresthesia). If the connective tissue is formed on the pathological site without a previous violation of the integrity of the skin, then this process is called cicatricial atrophy.

Scale (squama) - a conglomeration of loosened horny plates.

Normally there is a constant desquamation of the epithelium, however this process is invisible to the unaided eye (physiological peeling). Mechanisms of scaly formation are parakeratosis (the presence of cells with nuclei in the stratum corneum) and hyperkeratosis (thickening of the stratum corneum). Parakeratotic peeling is a characteristic post-peeling reaction of the skin.

Depending on the size and type of scales, the mucoid is distinguished (resembles the dispersion of "flour"), pityriiform, or pitiriasiform (reminiscent of the dispersion of "bran"), lamellar (large and finely lamellar) and exfoliative (large layers) peeling.

The crust (crusta) is a dried exudate.

The color of the crusts can be used to judge the origin of exudate: serous exudate is poured into crusts of honey-yellow color, purulent - greenish-gray, hemorrhagic - brownish-black. In a number of cases, scales-crusts are diagnosed, that is, flakes impregnated with exudate. Crusts are formed more often after regression of the cavitary elements (vesicles, blisters, pustules) and ulcers.

A crack (fissura, rnagas) is a linear skin defect associated with a violation of its elasticity.

Causes of cracking are a decrease in the production of sebum (dry skin), maceration (swelling of the stratum corneum of the epidermis in a moist environment), keratosis (thickening of the stratum corneum) and infiltration in the dermis. The crack can be superficial (within the epidermis) and deep (penetrating into the dermis).

Abrasion (excoriatio) is the result of a mechanical trauma to the skin when it is combed.

It is the result of itching. Excoriations have a linear form, a comma or a triangle. Clinically, they are white bands of the loosened stratum corneum, or erosion, covered with hemorrhagic crusts, located dotted, or continuous linear erosions, covered with hemorrhagic crusts.

Eschara - limited dry necrosis of skin of black or grayish color, extending to different depths and firmly connected with the underlying tissues

May occur due to exposure to the surface of the skin of obligate factors of a physical or chemical nature (high temperature, concentrated acids, for example, in deep peeling, alkali, etc.) or as a result of microcirculation disturbances in the zone immediately adjacent to the lesion focus.

Pathological conditions of the skin include keratosis, lichenification, vegetation, dermatosclerosis, an antedoderm and atrophodermia.

Keratosis (keratosis) - layers of dense, dry, hard-to-remove horny masses waxy-yellow or grayish in color.

Lichenification (Lichenificafio) is characterized by a pronounced pattern of the skin, its thickening, dryness and brownish-cyanotic color, often peeling.

Vegetation (vegetatio) - formation above the skin (mucous) formation in the form of a "scallop". The surface of vegetation can be dry, according to that normal or thickened stratum corneum, and also moist and eroded (in folds).

Dermatosclerosis (dermatosclerosis) is the area of skin densification with a decrease in its mobility with respect to the underlying tissues. The skin is not folded into the crease, when pressing with a finger, the impression does not remain.

Anetodermia (anetodermia) - small areas of atrophy of the skin itself (dermis) whitish color with a wrinkled or slightly herniated surface. When pressing on these areas with a buttoned probe, the latter easily "falls" into the skin - a symptom of the "bell button", as in a void (Greek anetos - empty).

Atrophodermia (alrophodermia) - a different depth of skin or brownish browning over the areas of atrophy of subcutaneous fat of cellulose. The skin pattern is not changed. In cosmetology, secondary atrophodermia occurs, which is the residual phenomena at the site of the resolved inflammatory nodes at the sites of intramuscular injection or after liposuction (lipoaspiration) as its complication.

An objective examination of the patient is carried out according to generally accepted rules and includes both clinical and other methods of research (laboratory, instrumental). In addition, in the diagnosis and differential diagnosis of certain dermatoses use special methods of laboratory examination (for example, cytological, immunological). In dermatocosmetologists and widely used additional invasive methods for assessing the skin condition

trusted-source[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12]

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