In biology, it is customary to distinguish primary and secondary morphological elements of the skin, skin rash. First of all, spots and blisters are considered. In addition, doctors examine the vesicles and pustules. Existing terminology distinguishes elements: papules, nodes, small tubercles.
Spot
This primary morphological element of the skin is a zone that differs from the normal state of the integument by shade. Among the clinical signs of others not detectable - only color. The consistency and topography of the site correspond to a healthy environment. There are no features in the level of occurrence. The stain can be provoked by the inflammatory process or have a non-inflammatory nature.
Any doctor can tell about primary morphological elements that such a condition is provoked by an increase in the gaps of blood vessels through which blood flows. In this case, vascular spots belonging to the category of inflammatory are formed. The cause of the phenomenon is pathological processes occurring in the papillary dermal layer.
Case features
The color features of both primary and secondary morphological elements are determined by the nuances of the process that caused the formation. In particular, when it comes to spots provoked by the focus of inflammation, areas of different shades of red, from bright scarlet to cyanotic, are most often identified. The latter option is most characteristic of a continuously developing inflammation, a slowed blood flow, especially when the violation is expressed in veins. Red, pink - shades inherent in the disruption of the arteries.
Differential diagnosis of the primary morphological elements of the rash, provoked by the incorrect formation and regular expansion of blood vessels close to the upper layer of the skin, is carried out by pressing on the reddened area. However, some spots may fade, almost disappear. A similar result is observed when exposed to a glass slide. As soon as the pressure is removed, the shade returns to the former unhealthy. A long-existing inflammatory stain becomes a source of regular flow of blood-shaped structures into the skin. This leads to the transformation of the shade into brown, brownish, yellowish.
Spots: nuances and features
Primary morphological elements include roseola. This term refers to small areas of persistent redness due to inflammatory processes. The diameter of the roseola varies from a couple of millimeters to three centimeters. Roseola's form is an oval or a circle. General diseases caused by infection most often manifest themselves on the skin with just such elements. Certain pathologies provoke fused roseola. With measles, scarlet fever, this causes erythema.
Histological examination of roseola shows the expansion of vascular lumens and the filling of areas with blood beyond measure. In the presence of primary morphological elements of the skin rash, pathological changes in the upper third of the skin integument are most pronounced. As a rule, the endothelium swells; in some cases, the proliferative activity of cells is detected. Near the vascular region, the formation of lymphocytic infiltrate is possible. The formation of syphilitic roseola is associated with a mixture of plasma and lymphocytes in the infiltrate.
Erythema
Another primary morphological element is erythema, which is a large area of ββchange in the shades of the skin. The cause of the formation of erythema is the focus of inflammation. The diameter of the formation is from a couple of cm to tens. Such zones can be combined, covering impressive areas of the skin, which causes erythroderma. Erythema is possible active, passive. The first type is acute, indicates inflammation: the area swells. The area is hot to the touch, it burns or itches. Dimensions, shape, shade of the focus vary from case to case. If the formation appeared in the form of an oval or circle, it tends to grow. Such areas may merge to form garlands. In some patients, erythema remains stable for a long time - this is called fixed. A bright shade of red that accompanies the first moments, subsequently changes to pinkish, yellowish or indicating cyanosis.
When examining the primary and secondary morphological elements of a rash that are characteristic of a particular case, doctors must take samples for histological analysis. When it comes to erythema, as a rule, the study shows typical signs of inflammation. The vessels expand, an infiltrate is formed, whose composition depends on the nuances of the pathology. Erythema is characteristic of toxicoderma, neurodermatitis and many other diseases. Pathological processes cover not only the papillary layer, but also localized deeper elements. Edema is most pronounced in the outer third of the skin. Infiltrate is formed by lymphocytes, neutrophils, eosinophils.
Blister
Often this primary morphological element occurs with urticaria, but can also accompany other pathological conditions. The term is commonly used to denote a cavityless formation caused by acute inflammation. It appears due to capillary expansion of the dermal layer, accompanied by increased permeability of the vascular walls, through which a serous substance that does not contain protein inclusions seeps into the surrounding space. The process leads to the occurrence of an oppressive pressure vessel. A limited lesion appears on the skin surface, resembling a pillow, dense in structure. The shape of the blister varies from case to case, but the formation always rises above the main skin layer.
Initially, the element is characterized by a pinkish or red color due to vascular expansion. Gradually, the area turns pale, as the secreted substance squeezes the vessel. In a typical course, the element is white, resembles porcelain in color. This is especially pronounced in the center of the region. The periphery may be pinkish or red.
Features of the pathological condition
A blister is such a primary morphological element, which is characterized by a rapid appearance and equally short-term disappearance. In rare cases, the formation persists for a long time. He has a tendency to grow on the periphery. The foci can merge, while forming areas similar to garlands or rings. To some extent, the area resembles a map.
Occasionally, the surface may contain a bubble - this is characteristic of a situation in which exudate is produced very actively. Inside the vesicle contains a serous substance, possibly with bloody inclusions. The formation of a blister is usually accompanied by burning, the area itches. In some cases, the patient suffers from fever, malaise.
Blisters: Nuances
With a histological examination, you can see the swelling of the papillary and the layers of the skin below it. The vessels are sharply dilated, which is especially characteristic of those containing lymph. There is usually no infiltrate, less often there is, but the volumes are small. Moderate spongiosis is possible.
Most often, such a primary morphological element accompanies urticaria. Perhaps the appearance of blisters on the background of anaphylactic shock, serum sickness, dermatosis. Cases of blistering on visually healthy skin exposed to mechanical stress are known. In medicine, the phenomenon is called autographism. The resolution of the area is rarely accompanied by the preservation of traces, but there is a risk of pigmentation of the site.
Pustule
The primary morphological element denoted by this term is a flat formation, inside of which a purulent substance is contained. The abscess can be very small, no more than one and a half millimeters in diameter, but there are also large formations reaching several centimeters. For some they have the shape of a cone, others look like balls. The appearance of a flat pustule is possible. The nuances of occurrence in the skin allow you to divide all cases into superficial, deep. In the first, the content dries quickly, which leads to the formation of a crust. When it leaves, the area remains heavily pigmented for some time. This condition is called impetigo in medicine.
With a histological examination of the area, the pathology of which is explained by the invasion of strepto-, staphylococci, you can see the pustule under the stratum corneum. The area is filled with fibrin, specific white blood cells. In a small amount, lymphocytes can be found. In rare cases, acantholytic cells are found. Under the pustule spongy is possible. The upper skin layer is filled with an infiltrate, which mainly contains lymphocytes, neutrophils.
Pustules: features
This primary morphological element of psoriasis and other skin pathologies can form near the hair follicle. In this case, folliculitis is diagnosed. Pustules usually look like a cone, an erythematous crown is visible around. Folliculitis can be superficial or localized at the mouth of the follicle. In addition, the process can be deep, covering the entire follicle. This is accompanied by the most pronounced pain syndrome, the damaged area is brightly colored. There is a risk of necrotic core formation. After the healing of the area, a scar remains.
If the pustule appears on the surface, does not belong to the number of follicular, diagnose a conflict. Visually, it looks like a bubble, the surface is sluggish. This is more common with streptococcus infection. If the pathology is localized in the dermis, ecthyma is detected. It can become covered with a layer of crusts, becoming like a snail. This is due to suppuration, leading to the generation of rupees. When the top layer is destroyed, or the crust is removed, a deep ulcer appears. As it heals, a scar remains.
Pathologies and diagnoses
Pustule is such a primary morphological element, which is most often explained by infection with staphilo-, streptococci. The generation of purulent discharge is associated with a deterioration in local or general immunity, which is possible due to a lack of vitamins in the body and under the influence of other aggressive factors.
One of the types of pustules is spongioform, named after Kogoy. This is a multi-chamber formation that appears in the epidermis in the upper part. The peculiarity of the region is the numerous cavities within which neutrophils can be found. Here are the cellular elements of the epithelium, the remains of the membranes that underwent destructive transformation. Pustula Kogoya is always accompanied by swelling, vascular expansion, the appearance of infiltrate. This type is widespread in patients with psoriasis, often accompanied by keratosis, candidiasis, Reiter's disease and acrodermatitis.
Bubble
This primary morphological element is a small cavity filled with a serous substance, possibly with blood inclusions. As a rule, the vesicle is located above the skin level, visually similar to the hemisphere. Diameter varies from one and a half to five millimeters. With dyshidrosis and some other pathological conditions, the bladder is on the same level with the skin, but is visually visible, as if it were visible through healthy layers. Specific features are determined by the depth, skin nuances, the thickness of the stratum corneum.
The vesicle is usually accompanied by edema. Often, vesicles form with eczema, herpes. Transillumination through the covers is possible, giving rise to associations with sago grains. As a rule, a lot of bubbles appear, they can connect, which leads to the appearance of multi-chamber regions. Group rashes, the formation of surface nodules are possible.
Histological examination of the vesicles reveals exudate, spongiosis, the presence of single-, multi-chamber vesicles. The former are more common in dermatitis, the latter are more characteristic of herpes. If the vesicles consist of one chamber, spongiosis is detected in different skin layers. The epidermal cells proliferate, the vesicle rises, remaining under the stratum corneum.
Bubble
This term refers to the formation of a cavity whose diameter is more than half a centimeter. Sometimes bubbles grow to seven centimeters, occasionally they become even larger. Inside the area is filled with liquid substance. As a rule, the bubble is clearly defined, as the base - an oval or circle. The formation stands out above the main skin level. Mostly one with a single camera, it quickly disappears after a puncture. Less commonly, bubbles merge. This is observed, for example, with epidermophytosis. Education is becoming multi-chamber.
Bubble features
Sometimes the formation has an irregular shape. Dimensions, outlines in this case repeat the boundaries of the influence of some aggressive external factor that caused the bubble to appear. For example, this is observed in contact with poisonous plants or chemical compounds. The tire of the area is flabby, but can be stretched. Inside, there is a serous fluid in which blood elements may be present.
Like vesicles, vesicles can be of inflammatory origin. Observation around the redness area is possible. This is more characteristic of erysipelas, dermatitis, erythema. With some forms of pemphigus, pemphigoid, epidermolysis, the skin remains normal, there are no visible changes.
Papule
The term refers to a cavity-free formation that is located on the surface and stands out above the main skin level. The consistency of the zone is soft or dense. As a rule, after the disappearance of the papule, there is no cicatricial change. The cause of the appearance may be a focus of inflammation, but non-inflammatory pathological processes are also distinguished. In the case of inflammation, the papule is associated with cell proliferation in the skin layers, the formation of infiltrate, vascular expansion or swelling of the tissues.
If you press on the area, the papule turns pale. This is characteristic of patients suffering from syphilis, deprivation, dermatoses of other types and forms.