RASH

RASH, the visible manifestations on the skin that appear as a result of pathological-anatomical changes in the substance of the skin from various producing factors that directly affect the skin (physical, chemical, bacterial, etc.), as well as from internal causes (general infectious diseases, toxic causes, etc.), and such rashes are called exanthemas. Rashes can appear not only on the skin but also on mucous membranes, with the rash on the latter being called enanthema. Both exanthemas and enanthemas consist of individual rash elements or efflorescences. Individual rash elements, depending on their morphological features, are divided into various types, or primary efflorescences, and depending on the further course of the disease process or as a result of its reverse development, primary rash elements can undergo various modifications (for example, the appearance of scales, crusts, etc. on their surface), which already refers to secondary changes of efflorescences. In dermatology, primary efflorescences and their secondary changes are distinguished. Primary efflorescences: 1) spot (macula, s. roseola), 2) papule (papula), 3) tubercle (tuberculum), 4) nodule (tuber, phyma, gumma), 5) tumor (tumor), 6) wheal (urtica), 7) vesicle (vesicula), 8) blister (bulla), 9) pustule (pustula). Secondary changes: 1) scale (squama), 2) crust (crusta), 3) erosion (erosio), 4) excoriation (excoriatio), 5) fissure (rhagas), 6) ulcer (ulcus), 7) scar (cicatrix), 8) pigmentation (pigmentatio), 9) atrophy (atrophia). The pustule forms its derivatives: impetigo, ecthyma, rupia. The diversity of primary rash elements and their secondary changes depends on various pathological-anatomical changes in the substance of the skin. Where only hyperemia of the skin is the basis, redness (erythema) occurs, which can be diffuse over a larger or smaller surface area of the body (for example, redness from a first-degree burn, etc.). In some cases, however, with a number of skin or general infectious diseases, erythematous redness appears in the form of numerous, separate, limited spots, or roseolas. In such cases, we are talking about the appearance of roseolar rash. Where the appearance of a rash depends on small foci of infiltration of the superficial layers of the skin, which is manifested by the formation of nodular elements on the surface of the skin, we are talking about papular rash, etc. The morphological features of individual primary and secondary rash elements are as follows: a roseola is a small, round, clearly defined erythematous spot that does not rise above the skin surface, disappearing from pressure and reappearing after the pressure is released. It occurs in the form of abundant roseolar rash in some general infectious diseases (measles, rubella, scarlet fever, typhus, syphilis, etc.), with toxic factors (for example, internal or subcutaneous use of some medications) and some skin diseases. With reverse development, the spots disappear without a trace, in some cases - with peeling of the skin; sometimes at the site of a long-existing spot, skin pigmentation remains. Spots of a spotted nature, depending not on hyperemia of the skin but on other pathological-anatomical phenomena in the skin, are also included in the category of spots. Spots appearing due to hemorrhages into the skin have a bluish-violet color, subsequently turning greenish, yellowish, and brownish (hemosiderin pigmentation persists for a fairly long time). In size, hemorrhagic spots are divided into small ones - petechiae, larger ones - ecchymoses, band-shaped ones - vibices. Hemorrhagic spots owe their origin to trauma or other causes, sometimes of toxic or infectious nature (purpura rheumatica, morbus maculosus Werlhofii, hemorrhagic forms of smallpox, measles, typhus, syphilis, etc.). Blue spots - maculae coeruleae - are the result of flea bites, they do not disappear from pressure and persist for a long time. Pigment spots - see below (secondary changes of efflorescences). Papule (papula) - a more or less dense nodule ranging in size from a pinhead to a lentil grain or larger. Papules in their color, size, density, localization, course, sequential changes, etc., depend to a large extent on the underlying disease. Typical papular elements are found in syphilis, and here too they have different sizes in different cases; sometimes scales or crusts appear on their surface, and sometimes they turn into pustules. Syphilitic papules are quite dense to the touch, with a brownish-red tint. In lichen planus, papules are usually small, with polygonal outlines, with a flattened or slightly depressed surface, shiny appearance, arranged in groups in the form of disks, rings, etc. In some diseases, the rash consists exclusively of small papules, usually of the same size, often arranged in groups of various outlines, and sometimes evenly scattered on different areas of the body surface. Such diseases are designated by the term lichen (lichen ruber planus, l. r. acuminatus, l. scrofulosorum, l. nitidus, etc.). A tubercle differs from a papule essentially by its deeper location in the thickness of the skin and its tendency to break down in the central part with subsequent ulceration, which heals with a scar. The size of tubercles varies depending on the underlying disease, ranging from a millet seed to a pea or even somewhat larger. In some forms, the density is significant (for example, in tuberculous syphilis), in others the consistency is soft (for example, in lupus tubercles). The color can vary in shades from red to brown. Tubercles can be located in separate groups or scattered in different places on the body surface. A nodule is an even larger formation resulting from an infiltrate located deep in the skin or even deeper. Nodes reach the size of a walnut, and sometimes larger. They often break down in the central part, and the entire tissue of the node can break down, opening outward to form a fistula passage or a deep ulcer. Syphilitic nodes (as well as scrofulous nodes) are called gummas. In some diseases, the infiltrates of nodes are located more superficially (lupus tuberosus, s. tumidus, erythema nodosum, lepra tuberosa, jodo- and bromoderma tuberosum, etc.). A tumor is the result of a neoplasm of tissue of one kind or another from the skin or more deeply located tissues (see Tumors). A wheal is a formation somewhat elevated above the level of the skin, of more or less regular round outlines, depending on the edema of the epidermis on a limited area. Typical wheals are noted in nettle burns, as well as in the skin disease known as urticaria (see). Closely related to urticaria are the so-called dermographism and acute angioneurotic edema of the skin (dermographismus, oedema angioneuroticum Quincke). Vesicles are small, hemispherical formations filled with clear serous fluid, located in the superficial layers of the epidermis, the horny layer of which forms the covering of the vesicle. The contents of the vesicle is serous fluid accumulating in the Malpighian layer of the epidermis, and sometimes vesicles arise due to the retention of sweat in the superficial layers of the epidermis (miliaria crystallina, dyshidrosis). In some diseases, vesicles are located in separate groups; such diseases are designated by the term herpes (h. simplex, s. febrilis, h. labialis, h. genitalis, h. zoster; see Herpes). Blisters differ from vesicles by their larger size, reaching the size of a walnut or even larger. In some skin diseases, blisters are the only manifestation on the skin (pemphigus vulgaris, epidermolysis bullosa, etc.). A pustule differs from vesicles and blisters by its purulent contents and more pronounced inflammatory phenomena from the bottom and surrounding part of the skin. Pustules can arise independently as such or by suppuration of the superficial parts of a papule. The size of pustules varies widely - from the size of a millet seed to a pea or even a walnut. The contents of pustules include pus-forming bacteria. Pustules can be single-chamber and multi-chamber (for example, smallpox pustules), the surface of these pustules appears somewhat 'umbilically' depressed. Pustules dry into a crust, under which healing occurs without scar formation, and in some cases a scar forms (smallpox). As derivatives of pustules, the following formations are distinguished: impetigo - a slight erosion at the site of a preceding pustule; ecthyma - a more significant formation in circumference and depth of an ulcerative nature, healing with a superficial scar; rupia - a crust-covered ulcer that tends to spread in circumference and depth with a simultaneous increase in the size of the covering crust.

Secondary changes of the rash elements consist of various changes to the surface of the primary elements or the skin itself in places where primary elements formerly existed. - Scales represent layers of cells from the horny layer of the epidermis resulting from its peeling off. There are distinguished fine bran-like scales, plate-like and layered scales. - Crusts are the result of drying up of vesicles or pustules, as well as of areas of skin denuded of the horny layer (due to mechanical causes or as a result of a former pathological process). - Erosion is a limited loss of the horny layer of the epidermis, with the moist, shiny Malpighian layer being exposed. - Excoriation is the mechanical removal of the horny layer of the epidermis. - Fissure is a linear rupture of the skin coverings to a greater or lesser depth. - Ulcer is a greater or lesser loss of substance of the skin coverings, usually depending on a local pathological process, with a purulent base and inflammatory phenomena in the surrounding parts. The tendency to heal is sometimes slight or absent; after healing, a scar remains. - A scar is formed as a result of healing of an ulcerous surface or deep tissue defects, with the dead tissue being replaced by connective tissue. Scars may have an atrophic appearance, and sometimes they appear excessively hypertrophic, massive - so-called keloids (see). - Pigmentation is the excessive deposition of skin pigment in places where primary elements formerly existed (e.g., papules), in size and configuration completely corresponding to the former efflorescence. Sometimes pigmentation appears in places where former inflammatory foci of the skin existed, although such pigmentation, like some other types of it, does not belong to the secondary changes of primary elements. - Atrophy of the skin may develop as a result of the regression of certain primary elements, leading to degenerative changes in the skin (e.g., after the resorption of syphilitic tubercles). Both primary elements and their secondary changes are noted in various skin diseases or general diseases. In some diseases, uniform rash elements are present (e.g., pustules in smallpox, nodules in lichen planus, vesicles in pemphigus, etc.) - in such cases, we speak of monomorphic R. In some diseases, however, various rash elements may be present simultaneously (e.g., along with roseolas there may be papules and pustules, as is sometimes noted in secondary syphilis; or along with spots there are wheals and vesicles, as is noted in exudative multiform erythema, in Duhring's disease, etc.), and such a combination is called 'polymorphism' of R. In contrast to this true polymorphism, there is also the so-called 'false polymorphism', in which uniform rash elements are in different stages of development (e.g., the simultaneous existence of fresh pustules and pustules that have dried into crusts; or in papular R., some papules are covered with scales or crusts, etc.).