Visual inspection of the skin
Skin color changes are local or common. Blanching and reddening of the skin can alternate due to fluctuations in the blood supply in people with labile vegetative nervous system. Permanent and often increasing pallor is observed with a decrease in the hemoglobin content in the blood (anemia, anemia ), for example, in acute blood loss or in various blood diseases. Whitening with a sensation of numbness, for example, of the fingers (a symptom of "dead fingers") is observed with vasospasms - Raynaud's disease. The skin and mucous membranes may acquire a bluish tint (cyanosis) in heart failure with blood stagnation in the great circulation and an increase in the content of restored hemoglobin in the blood. A peculiar pale-coffee shade (the color “coffee with milk”) acquires the skin with an untreated subacute infective endocarditis, with uremia, the skin is pale greenish (anemia with a delay in the skin of the urochromes).
The icteric staining of the skin is observed in diseases of the liver and biliary tract as a result of the accumulation of bilirubin in the blood (hyperbilirubinemia), which can also be formed in large quantities during the breakdown of red blood cells (hemolysis). First of all, yellowness appears on the sclera, then it spreads to the mucous membrane of the oral cavity, the skin of the palms, and other areas. With prolonged severe hyperbilirubinemia, jaundice may acquire a greenish or dark ("earthy") shade.
In adrenal insufficiency, the skin looks tanned, which is also noted in hemochromatosis (a delay in the tissues of iron). Consuming large amounts of certain foods (for example, carrot-containing carrots, tomatoes) or taking certain medicines can also cause changes in skin color.
Loss of pigment in certain areas of the skin occurs in the form of vitiligo - depigmented white spots, often located on symmetrical areas.
A characteristic appearance is acquired by the skin of the face in many patients who abuse alcohol: the skin of the nose and cheeks has a purple-cyanotic hue, there is a marked dilation of the vessels of the sclera.
Various diagnostic rashes acquire great diagnostic value . Thus, in the case of a number of infectious diseases, they often “open up” the diagnosis, in other cases they help to differentiate the disease. Hemorrhages and small hemorrhagic (petechial) lesions occur in various pathologies and not only in connection with bleeding disorders. Large-spotted reddening of the skin (erythema) have a different origin. The so-called erythema nodosum on the anterior surface of the tibia with painful compaction of the erythematous skin area is most often observed in sarcoidosis, as well as in tumors, drug intolerance, and tuberculosis. For example, for diagnosis, hemorrhagic rash is of great importance as a manifestation of hemorrhagic vasculitis — primary ( Schönlein – Genoch disease ) and secondary (in chronic liver diseases, some tumors).
On examination of the skin, it is possible to detect trophic disorders, bedsores in areas that are subjected to prolonged pressure, as well as moles, tumor formations ( basal cell carcinoma, rarer tumors, tumor metastasis). Attention should be paid to the tattoo, during which it is possible that the hepatitis B and C viruses enter the body, which helps to understand the etiology of detected changes in the liver and other organs. Postoperative scars after the opening of abscesses, fistulous passages also need to be fixed. Traces of minor burns on the skin are often found in persons suffering from alcoholism.
Various skin changes are observed in systemic connective tissue diseases. When systemic lupus erythematosus is characterized by the appearance of erythematous rash on the cheeks in the form of butterfly wings, bridge of nose. With systemic scleroderma, masking the face, the disappearance of facial expressions, the appearance of folds around the mouth in the form of a pouch are noted.
Livedo (lat. Bruise) - a special condition of the skin, characterized by its bluish color due to the mesh or tree pattern of vessels translucent through the skin. There are the following types (stages) livedo:
- marbling of the skin;
- mesh livedo - livedo reticularis;
- treelike livedo - livedo racimosa.
Most often, livedo is observed in systemic lupus erythematosus, Sneddon syndrome, nodular periarteritis, in addition, it can also be observed in other diseases: dermatomyositis, systemic scleroderma, infections (tuberculosis, dysentery malaria ); a link with hyperproduction of antibodies to phospholipids (cardiolipin, phosphatidylserine) is noted, the pathogenetic significance of the latter in the development of life is discussed.,
Xanthomas in the form of whitish spots, rising above the surface of the skin, are associated with the deposition of cholesterol.
Peculiar dilatations of the skin vessels ( telangiectasia ) in the form of "spider veins" are observed in chronic liver diseases ( cirrhosis of the liver ).
Hypersensitivity skin reactions (allergies) to various substances, primarily to drugs and food products, can manifest themselves by various rashes and itching, for example, the so-called urticaria.
Rapid hair loss is observed, for example, in systemic lupus erythematosus. Hirsutism, i.e., excessive growth of hair on the face, body, legs, is observed in young women as a result of an excess of circulating androgens (male sex hormones). When hypogonadism, i.e. Decrease in the function of the gonads, both in men and women, there is an insufficient growth of hair in the region of the armpit fossa, pubis.
Nails can be modified for various diseases. The most well-known are the changes in the terminal phalanges of the fingers, which take on the appearance of so-called drumsticks, while the nails look convex, like watch glasses (Hippocrates fingers). Similar changes are observed in chronic suppurative diseases ( bronchiectasis,, osteomyelitis ), as well as in infectious endocarditis, chronic liver diseases, and congenital heart defects. With a prolonged iron deficiency, the nails may become flat and then spoon-shaped (koilonhia).
Feeling of the skin is usually done along with its examination. At the same time, it is possible to detect increased dryness or, conversely, skin moisture. Excess sweating is observed with increasing body temperature, hyperthyroidism, hypoglycemia, with tides in women during menopause, some nervous conditions, pain, fear. Excessive sweating is observed with tuberculosis, infective endocarditis. Sometimes with increased perspiration, a special rash ( prickly heat ) appears in the form of bubbles the size of a poppy seed, covering the skin like dew. Sweat contains most of the blood electrolytes, but at a concentration that is significantly less than plasma. Sometimes a study of the composition of sweat can provide valuable diagnostic information. Thus, in cystic fibrosis, a characteristic increase in the concentration of sodium chloride in sweat is noted; in diabetes mellitus, the content of glucose increases in sweat, which predisposes to infection of the skin ( furunculosis ).
When palpating, you can also detect a local increase or decrease in skin temperature. Increased temperature may be associated with increased blood flow during inflammation, for example, erysipelas, with deep vein thrombophlebitis of the legs. Lowering the temperature of the limbs is observed in violation of the arterial blood flow.
When feeling the skin is determined by its elasticity or elasticity, which depends on the condition of its colloids and blood supply. With aging and some chronic diseases with loss of fluid, the elasticity of the skin decreases, it is easy to take it in the fold. Especially sharply skin elasticity is reduced in Ehlers-Danlos disease.
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Evaluation of the appearance of the skin
Visual analysis of the skin is important for primary diagnosis and for testing cosmetic preparations. Today there are several types of systems that allow you to quickly and comfortably conduct an objective assessment of the appearance of the skin. The assessment is based on two main parameters:
- surface topography and
- color of the skin.
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Impression method (replica method)
The skin cast is obtained by applying a thin layer of a special composition (nitrocellulose or silicone) on it. The composition, hardening, forms a film, the inner surface of which repeats the surface of the skin. After the impression is taken, the relief surface is scanned, the data is digitized and analyzed. So determine the density of wrinkles (the number of wrinkles per unit of surface), their area and depth. The surface of the impression is magnified under a microscope and photographed; The resulting gray image is digitized and the parameters characterizing the skin texture are calculated.
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Direct optical skin scan
A few years ago, the method of casts was perhaps the most common way to study the topography of the skin. Nevertheless, it has a number of inconveniences associated primarily with the manufacture of the cast itself. Therefore, the search for alternative methods did not stop. Today, a new generation of technologies is coming to replace it - contactless, fast, safe and accurate, carrying out direct optical scanning of the skin surface.
Modern devices are equipped with powerful computers with specially designed computer software that allows, among other things, to edit volumetric color images.
As an example, we present PRIMOS, a system for optical three-dimensional skin analysis developed by the German company GFMessetechnik GmbH. The PRIMOS scanner is a complex optical device consisting of a set of micromirrors, which “read” information from a scanned surface at different angles. The measuring accuracy of the scanner is impressive: it distinguishes points that are from each other at a distance from a few millimeters to several microns! PRIMOS takes a topographic image of the skin surface and, based on the resulting image, evaluates the relief, for example, determines the degree of roughness, “digitizes” wrinkles, scars, and so on.
Another example of a direct scanning system is SIAScope, which is an advanced dermatoscopy method (Astron Clinica Ltd., UK). Based on the spectral analysis of light reflected from the skin surface, the SIAScope receives information about its state. To do this, SIAScope illuminates the skin with an invisible or near red light that is safe for the body, and then registers the reflected light, consistently receiving 8 images at wavelengths from 450 to 950 nm (from blue to near red). The resulting combined image is a circle with a diameter of 11 mm with a resolution of more than 900 points / mm 2. Next, the image is analyzed in accordance with the optical model of the skin, according to which the skin color depends on the main chromophores - melanin and hemoglobin pigments; the extracellular substance of the dermal layer, consisting mainly of collagen fibers, also contributes to the skin tone. The original dermoscope image is decomposed by spectral characteristics into several so-called SIAgraphs (SIAgraphs), the analysis of which allows conclusions to be drawn about the level of skin pigmentation, blood supply and the state of the dermal matrix. The method is highly sensitive and has been tested in a number of major clinics, where it has proven itself, in particular, for the rapid diagnosis of melanoma.
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