Scabies: symptoms and treatment
- Features of the life cycle of the itch mite
- Symptoms of scabies
- Diagnosis of the disease
- Treatment of scabies
Scabies is a skin disease caused by the parasitizing of the scabies (Acarus scabiei) in the superficial areas of the skin.
Scabies is known for a long time. Mention of her are found in Egyptian parchments. In ancient China and Babylon, this disease was also well known. Ancient Greek Aristotle even cites in his works a description of "the smallest animals" in the blisters of rashes on the skin of sick people.
At the present stage, the most widespread of this disease is observed in socially unadapted groups of the population. Its outbreaks are observed in dysfunctional regions of the world, where mass migration of population takes place under the influence of natural disasters and military operations.
In regions that are safe in this sense, no one is immune from this disease either. So, the appearance of one infected person in a group of people united for a while (from a trip on a bus to a long-term stay in one room - kindergarten, school, boarding school) already allows to assume the presence of a potential source of the disease. The greatest risk of getting sick in the age ratio is for people of youth (25-35%). This is due to the greatest contact activity in the groups both during the training (school, technical school, institute) and after it (informal connections, a courtyard, a boarding school, a hostel).
Increased risk of getting scabies is promoted by active migration processes of socially unprotected population groups in the context of globalization of the surrounding world. Some risk is borne by mass tourism, especially extreme destinations, to exotic countries of the world, where this disease is quite common.
Features of the life cycle of the itch mite
An adult female of an itch mite, about 1/3 mm in size. Their photo is on the right. Males are about 1.5 times smaller and have no significance in the clinical picture.
Like all insects, in its development, scabies mites pass through the larval and adult stages. After fertilization, the female is implanted into the superficial skin (epidermis). Eating epidermis, it moves, laying in it the passages, where, apart from the products of its vital activity, it leaves eggs. In one intra-epidermal course, 3-4 fertile eggs can be identified at different stages of development. Above the place of masonry, females make holes to facilitate the appearance of offspring on the surface of the skin. On the skin, the larvae, spreading around, penetrate the hair follicles (the roots of the hair), under the keratinizing scales of the skin, into various elements of the rash (especially the bubbles). There they undergo a transformation, bypassing the intermediate stages, immediately into adult mature mites. On the human skin, mating occurs, after which, the females penetrate into the epidermis, and the males become cleaned by combing, separated from the micro flakes of the skin and die. The average life span of a female is 6-8 weeks, during which time it lays about 60 eggs. It is estimated that the potential yield of adult mites from one female in three months can reach up to 150 million individuals.
Removed from the skin, in the environment at room temperature, itch mites can maintain their viability for about a week. Under less favorable conditions, females live about three days, and larvae - about two days.
Symptoms of scabies
Scabies are of the following types:
- Typical, classical.
- Without itch moves.
- Norwegian scabies.
- Scabies of "cleanliness", or scabies "incognito".
- Complicated scabies.
- Scabious skin lymphoplasia.
A typical (classical) form of scabies
The main sign that attracts attention is a strong, intrusive itch. Itching is a reaction of the body to irritation by the products of the mite's vital activity. It is the response of the immune system, one of the parts of the external manifestation of which becomes and the sensation of itching, restrains the unrestrained reproduction of the parasite, the outcome of which could be death. With special force, sometimes even depriving sleep, itching manifests itself in the evening and at night. This is due to the greatest activity of the female tick at this time. The main occupation of her during this period is the paving of intra-epithelial strokes.
Scabrous strokes are the most characteristic feature of scabies. From each turn the female gnaws one or two branches, making several outlets in them. In each of the knees fertilized eggs are laid. Further, it continues to move in the main course. With the onset of the morning and up to the middle of the day, the activity of the female drops sharply, and simultaneously at all individuals.
When the skin is exfoliated, the old passages are gradually detected as whitish lines, like surface scratches left when the needle is pierced with the tip. Figures have their own periodicity and repetitions, which can be used to judge the diurnal movement of the course.
The length of the diurnal course rarely exceeds 5 mm., And in its entire life the female passes about 3-6 cm. It is theoretically possible to identify itching motions on any part of the body, but the most probable location in areas with a thickened superficial epithelium. Such areas are the skin of the hands and feet. The thickness of the epidermis layer, which is present here, allows the larvae to hatch from the eggs long before the keratinous layer is repulsed. In addition, to maintain the life cycle does not require too high a temperature of the skin.
The reaction of the body to the introduction of the tick is also the appearance of rashes in the form of small, red hillocks (papules) 1-2 mm in diameter, rising above the rest of the skin, sometimes having bubbles (pustules) filled with liquid on their tip. The first rashes of this type can be detected above the site of introduction of the tick into the skin. You can see photos of rashes under scabies on the right.
The number of papules, as a rule, depends on the number of introduced ticks. Eruptions can be initially multiple and "sprinkled" after the emergence of new sexually mature individuals.
Scabies rash, along with itch moves, can often be found in the interdigital folds of the hands, feet. They can also be identified on the flexor surfaces of the wrist joint, on the lateral surfaces of the fingers, in the armpits in the front, in the peripodal region, on the inner surfaces of the thighs, buttocks. As an option, there is an arrangement of itch moves in men on the skin of the penis, in women - around the nipples.
For children, due to the peculiarities of the structure of the skin, the most characteristic localization of rashes and strokes on the palms and soles.
With severe itching and subsequent combing, the rash, due to infection, takes on a pustular appearance, with yellow crusts. It is possible to attach inflammatory skin diseases, up to furuncles and carbuncles. It is possible to join erysipelas and dermatitis.
Other symptoms of typical scabies
In addition, a long history of observations of scabies has made it possible to identify a number of characteristic symptoms according to the authors, which make it possible to differentiate this disease from skin manifestations of other diseases:
- A symptom of IA Gorchakov-Ordi (the appearance of pustular rash and pustules in the extensor sections of elbows, with the presence of crusts with staining of blood);
- A symptom of Michaelis (the appearance of bloody crusts in the interannual area against the background of enlightened skin areas);
- A symptom of Cesari (palpation of the parasite and scabies in the form of slightly perceptible elevations during palpation of the alleged site of tick localization, determined in the presence of single skin elements of the rash).
Regional lymph nodes can also be increased.
Scabies without intraepithelial itch moves
It is extremely rare. In these cases, infection is not carried out by a mature individual, but at the stage of development of the tick in the stage of the larva. The rarity of this form of scabies is explained by the fact that for the retention on the surface of the skin and the introduction of the parasite it is necessary to have a developed gnawing oral apparatus, which the larvae do not yet have. Individuals, who could stay and penetrate into the hair follicles - cause a pronounced immune response to the stimulus. There is a strong itch and a rash of an allergic nature, not only in those places where the larva penetrated, but also throughout the body. Accordingly, until the larva ripens into a mature female (and this should sometimes be up to two weeks) and does not penetrate the epidermis, itching can not be detected in the areas of the rash.
Named in this way, because it was first described in Norway in patients with leprosy (leprosy) in the middle of the XIX century. This is the most contagious and malignant in its current form of scabies. It occurs in individuals who have a persistent background inhibition of the immune system for various reasons. For example, after the passage of chemotherapy for cancer, with hormone therapy of a part of severe diseases with corticosteroids. The risk of severe illness is in people with Down syndrome, HIV-infected people. Skin sensory abnormalities observed in paralysis of various etiologies, some other diseases, congenital features of keratinization of the skin can also contribute to the transition of the classical form of scabies to Norwegian.
- A variety of rash elements, having a draining character, from spots, to blisters, the presence of ulcerated cracks in the skin.
- The appearance of crusts of various shades of yellow and brown. Increasing in thickness and merging, they can form a kind of "shell" over the parts of the body.
- In the crusts, when studying them, a large number of mites are identified at different stages of their life cycle. Sometimes, their number reaches 200 per cm².
- Identify the parasite and can be on the nail plates, which, under the influence of the fungus and the flora, thicken and become loose, convenient for the dwelling of the tick and the development of its offspring.
- Adherence to the described picture of extensive pustular lesions of the skin, furunculosis, due to the attachment of a secondary infection.
- A prolonged temperature rise is observed.
Scabies of "cleanliness", or scabies "incognito"
- This form is characterized by the smoothness of the classical clinical picture due to the professional (doctor, confectioner, cook, etc.) and due to personal characteristics - cleanliness.
- New moves are not actually formed, the manifestations of itching are minimal, and the single elements of the rash are explained by the allergy to detergents.
- The spread of the disease to other parts of the body due to the permanent mechanical removal of mature individuals and larvae during washing does not occur.
- Scabrous strokes are sporadic.
The danger of patients with this kind of scabies is that, due to their apparent cleanliness outside, no one regards it as the primary source of outbreaks. And the infected person does not consider himself sick with any disease.
However, complete self-healing does not occur in such cases, since the maximum yield of ticks on the skin occurs at night, when the unsuspecting patient sleeps and does not perform the usual ablution.
With this form of the disease there will be a clinic of complications in the form of dermatitis, furunculosis of the skin, erysipelas, abscesses and phlegmon soft tissues. Occasionally, the disease can occur in the form of mild urticaria, as a complex response of the body to a foreign antigen. This will be the main treatment.
Accordingly, the disease will continue for a long time, and the patient will keep its danger to others, as a permanent source of scabies.
It is manifested by the appearance of a rash in the form of blue-purple nodules (papules) stretched out in small lines. They appear in the projection of itch moves and are most often observed on the inner surface of the thighs, on the scrotum, buttocks, elbows, on the mammary glands of women. These towering redness over the strokes are explained by an allergic reaction and a close finding of the lymph nodes in these zones. Evidence of this is the appearance of this type of rash in the same places with repeated infection with scabies.
This infection of scabies mites, parasitic exclusively on animals. The difference is that the infection is carried out by larvae, and not by adult mites, and the disease manifests itself immediately. The implantation is carried out in the open areas of the skin, which is explained by the penetration of the larva into the hair follicle. Until the hidden areas of the skin, because of the inability to stay on the surface, the parasite does not reach. When the sexually mature age is reached, the mite either perishes, or is scraped off the surface of the skin. Thus, after a brief itch and rash, self-healing occurs.
Diagnosis of the disease
In addition to the classical clinical picture, it is necessary to confirm the presence of a parasite at different stages of its development. This is achieved by extracting it with a needle.
In addition, under the microscope, the surface sections of the skin (epidermis) obtained by layer-by-layer method and thin-section method are examined using express diagnostics using 40% aqueous solution of lactic acid.
Treatment of scabies
It is carried out with the help of anti-scratch agents, the choice of which is quite large in recent times.
The difference from the previous generation of such drugs was the high rate of onset of the therapeutic effect in the absence of any side effects.
Most often used spregal, benzyl benzoate.
Drugs are applied to the entire body in the evening, carefully rubbing, especially paying attention to the characteristic habitat for the parasite. The drug remains on the skin all night, and in the morning the patient is thoroughly washed. To improve the effect, it is recommended to repeat this procedure after 2-3 days.
In complicated cases, antibiotics, antihistamines and hormonal ointments are connected to the therapy described. In these cases, treatment should be under the guidance and supervision of a physician.
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