Scabies is a contagious skin disease, the occurrence of which is provoked by a parasite — a scabies mite. You can get scabies by contact, it is transmitted from person to person through hands, underwear, clothes. Even a door handle or handrails in public transport can serve as a source of infection. Both adults and children are infected with it. It often happens that several family members get sick. Scabies is also transmitted during sexual contact with an infected person, so it is sometimes referred to as sexually transmitted diseases. For the first time, scabies as a skin disease was described more than 2500 years ago, but the etiology and pathogenesis were fully described in 1844 by the German dermatologist Ferdinand Gebra.
The content of the article:
Causes of scabies development and infection
The mechanism of infection with scabies
Symptoms of scabies
A typical form of scabies
Scabies of the clean
Nodular scabies
Cortical scabies
Diagnosis of scabies
Treatment of scabies
Scabies
There is an opinion that scabies has a wave-like character due to the development of tick resistance to scabicides. Also, in times of natural disasters, during the famine war years or when other social phenomena lead to crowding of people, there may be spikes in morbidity.
Scabies is seasonal. Most often, people become infected in autumn and winter, which is explained by the fecundity of ticks in September-December, cold leads to a decrease in sweating, and with it less antimicrobial peptides are released, which ticks do not “like”. In countries where climatic seasonality is not strongly pronounced, cases of the disease are evenly distributed throughout the year.
Causes of scabies development and infection
The causative agent of scabies is a scabies mite, a representative of the arachnid class. It is very small, it is almost impossible to examine it without a microscope. The female grows up to 0.5 mm, which is almost 2 times more than males. The scabies mite has a protruding oral organ, two pairs of anterior and two pairs of posterior legs with suckers.
Scabies mites mate on the surface of human skin, after that the males die, and the females make holes in the skin, bite deeper with their jaws and lay scabies passages. In them, females lay eggs, from which larvae develop, then adults, and after 2 weeks the process repeats. The female tick lives for 1 month, but during this time she makes a large number of moves under the epidermis, lays up to 4 eggs per day. The scabies mite multiplies so quickly that if it is not treated, then after 3 months it multiplies to 150 million. individuals.
In the scabies channels under the skin are located not only the eggs of ticks, but also the products of their vital activity. All this is toxic to the human body, so after a while an allergic reaction appears along with inflammation, which is manifested by severe itching of the skin. Since the scabies mite has the greatest activity at night, the itching increases in the evening, and at night it becomes unbearable. A person, combing itchy areas, transfers infection to healthy skin, the foci of infection increase.
The most convenient places for the settlement of scabies mites are palms and areas between the fingers, wrists, elbows, male genitals. There is little hair on these places, they are covered with a thick epidermis, contain a lot of sweat glands, which serves as a favorable environment for the development and life of scabies mites.
The mechanism of infection with scabies
Scabies is most often transmitted through prolonged or direct contact (contact sports, children’s games, handshakes). Infection takes about 30 minutes. Children, for example, become infected if they sleep in the same bed with infected parents. This is facilitated by the activity of the tick in the evening and at night. But there is a chance to get infected through the use of someone else’s underwear, towels, washcloths, sleeping bags. A moderately humid environment contributes to the survival of the tick for up to 5 days. The spread of scabies is characterized by localization in such collectives as a boarding school, dormitory, barracks, hospital, prison or in an antisocial environment.
When an individual of an adult scabies mite gets on the skin, infection with scabies occurs. After 2-3 hours, a characteristic rash may appear. Sometimes there is a hidden infection, the incubation period in this case lasts up to 14 days.
Symptoms of scabies
Scabies is characterized by three main signs: itching, which increases at night, nodular-vesicular rashes in certain places and scabies. These are the main clinical symptoms of scabies. At first, the patient discovers the first signs of scabies in his interdigital folds, abdominal area, groin, elbow bends, and thighs — bubbles that have appeared in pairs. They can also appear on the buttocks, genitals in men, mammary glands in women. The scabies mite chooses the most vulnerable places for the introduction. In young children, the soles, face, scalp, and then the entire body of the child may be affected.
On closer inspection, you can see uneven, thin lines barely rising above the surface of the skin, laid straight or zigzagged. These are itchy passages. Sometimes the move ends at the end with a transparent bubble through which you can see a white dot — the body of a tick. If no moves are detected, it may be scabies without moves.
A nodule appears at the site of the tick bite, when combing it becomes covered with a bloody crust. Permanent injury to the skin as a result of combing is complicated by the appearance of various types of purulent infection, the occurrence of an eczema process.
The primary rash manifests itself in the form of small erythematous papules, single or fused. The amount of rash does not prove the number of parasites, but indicates a pronounced allergic reaction to the discharge of a female tick. In infants, in addition to the presence of papules, scabies, vesicular rash appears, foci of wetness, paronychia and onychia occur. Scabies in children up to a year looks like urticaria, in complicated cases resembles eczema, sometimes nails can be affected — they become loose, thickened, crack. Intense itching brings anxiety to the child, sleep is disturbed, complications such as allergic dermatitis, pyoderma of the impetigo type, lymphadenitis, leukocytosis, albuminuria can develop, in infants this can provoke the development of sepsis.
A typical form of scabies
A typical form of scabies is characterized by all the symptoms: bubble-like paired rashes, itching, especially disturbing in the evening and at night, and scabby canals — passages. It is the most common. If the infection occurred through the hands, then itchy red spots appear between the fingers, on the wrists, thin, sinuous lines of scabies. In men, scabies moves to the penis, scrotum, infection of the entire body occurs, except for the face and scalp. The patient spreads the disease through his body by touching and scratching the foci of infection. Clothing also serves as a carrier of scabies mite on the body. That is why it is so important to disinfect clothes, bed linen, and treat the room during treatment. It is necessary to examine the patient’s family and people in close contact with him in order to avoid re-infection after the course of treatment. Scabies should be treated under the supervision of a dermatologist.
Scabies without moves develops after infection of the patient not by adults, but by larvae, which take some time to develop. There are no scabies, but there are bubbles.
Scabies of the clean
Scabies of the clean (“incognito” scabies) has less pronounced symptoms compared to the typical one. It occurs in people with a strong immune system or frequently washing patients who wash off the body of adult individuals of scabies mites. The disease is mild. With this type of scabies, there are isolated rashes and severe itching.
Nodular scabies
Nodular (nodular) scabies or scabious lymphoplasia is characterized by the presence of a few round itchy nodules or seals. Their diameter is from 2 to 20 mm, color — from pink-red to brown. Scabies passages are located on the surface. Nodular scabies is characterized by localization in the area of the scrotum, penis, inguinal and axillary folds, near the anus, on the inner surface of the thighs and buttocks, on the periarticular circles.
Sometimes these few nodules are the only sign of scabies. They will be a strong reaction of the immune system to the presence of ticks in the body and to the results of their vital activity. Seals are caused by the proliferation of lymph tissue in the skin. Even a few weeks or even months after an effective treatment, knots and itching can bother. The reason for this is unfertilized live female ticks, which do not have the opportunity to mate, reproduce offspring. They do not make holes in the roof of the passages, thereby limiting the access of the drug from the surface of the skin. Females live up to 4-6 weeks, secrete waste products, so treated patients have an allergic reaction in the form of itching for a long time.
Cortical scabies
Cortical (Norwegian or crustose) scabies was first described by Norwegian dermatologists Beck and Daniel lssen in 1848. Most often, this type of scabies develops in patients with disorders of the immune system or impaired skin sensitivity. Patients do not feel itching or cannot comb the foci of infection. This condition is characteristic of immunodeficiency, leprosy, syringomyelia, paralysis, senile dementia, as a result of regular intake of psychotropic drugs. Cortical scabies is characterized by pronounced hyperkeratosis, in the foci of inflammatory infiltrate there are up to several million ticks. If we compare that with a typical form of scabies, the number of ticks on the patient’s body is about 15 individuals, then we can imagine that a patient with cortical scabies, literally infested with parasites, is especially contagious.
When a person is infected with scabies mites from other mammals, pseudosarcoptosis occurs — a disease that has a short incubation period, there are no scabies passages. Ticks do not reproduce on an unusual host, the disease is not transmitted to other people.
Diagnosis of scabies
Domestic dermatology identifies characteristic eponymous symptoms that facilitate diagnosis: Ardi’s symptom: indicates the appearance of pustules and purulent crusts in the area of the elbows; Gorchakov’s symptom — bloody crusts on the elbows. The symptom of Michaelis signals the appearance of bloody crusts and impetiginous rashes in the crease between the buttocks with a transition to the sacrum; the symptom of Cesari reveals scabies, felt on palpation, as some elevation.
The final diagnosis is made after the analysis of clinical manifestations, laboratory and epidemiological data obtained after the examination. To do this, the following diagnostic methods are used: traditional — tick extraction and examination under a microscope; a thin slice of the epidermis of the scabies course will reveal both the tick and its eggs; layer-by-layer scraping of the scabies course; alkaline skin preparation.
Itchy passages will be better seen if you apply iodine tincture or ink to the skin. In some cases, a video dermatoscope is used, which allows you to increase the test up to 600 times.
Treatment of scabies
Scabies never goes away by itself and can last, sometimes worsening, for a long time. Nothing special is required for the cure, except the use of local remedies. It is only necessary to destroy the pathogen and its eggs. The drugs used for treatment can be conditionally divided into 4 groups. Synthetic derivatives of balsamic agents include benzyl benzoate.
Sulfur derivatives include sulfur ointments of various concentrations, Wilkilson ointment. Insecticidal preparations for the destruction of parasites include pyrethra ointments, K soap, flicide, lysol, creolin. Folk methods of combating parasites use gasoline, kerosene, gasoline, fuel oil, oil, ash liquor. Before treatment, the patient should wash off the mites from the surface of the skin, then rub the prescribed drugs into the affected areas. The drugs should be used according to their intended purpose.
To date, medicine recommends the use of more gentle and effective drugs for the treatment of scabies. For example, lindane, permethrin, crotamiton, spragal, which are produced in the form of a solution or aerosol.
To get rid of scabies, it is necessary to undergo a preventive course of treatment for all who have come into contact with the patient. During treatment, it is not recommended to wash and change bed linen, only at the end of treatment. The patient’s bed and clothes must be boiled and ironed with a hot iron. The remedy should be applied before going to bed.
