From Big Medical Encyclopedia

ITCH SKIN (pruritus cutaneus) — the peculiar, difficult giving in to definition feeling causing the need to scratch.

As feeling 3. to. represents the cortical process arising at impact of some irritants on the nervous device (see. Analyzers ). 3. to. can arise at influence of exogenous and endogenous irritants, and also at change of functions of the central and conduction parts of the nervous system owing to what 3. to. can be the central or peripheral origin.

Distinguish fiziol, the itch arising in response to adequate irritations (e.g., crawling and stings of insects), and patol, the itch arising at patol, conditions of an organism.

An etiology

the Reasons able to cause patol. 3. to., are extremely various. Bad attacks to its thicket are connected with hypersensitivity to food-borne or medicinal allergens (e.g., at reception of antibiotics, aminazine, a belladonna, etc.). Hron, form 3. to. it can be caused by the endointoxication arising at diseases of a liver, went. - kish. a path, at a helminthic invasion, and also at diseases of a metabolism.

The itch is observed as an epiphenomenon at very many dermatosis (urticaria, neurodermatitis, eczema, red flat deprive, a mange, etc.), but can arise and independently in the absence of any seen patol, changes of skin, being the main and only symptom of a disease of skin, usually in the form of painful attacks.

Quite often 3. to. — one of early symptoms of diseases of the hemopoietic bodies (leukoses, lymphogranulomatosis), malignant new growths, endocrine frustration, nervous and mental diseases. Considering that the itch arises only at some persons, it is necessary to believe that its basis are functional changes of c. N of page; perhaps also developing of purely mental, emotional itch.

The pathogeny

the Pathogeny of an itch is studied insufficiently. According to most of researchers, 3. to. represents not independent feeling, but modified feeling of pain, and only certain authors connect an itch with tactile sensitivity. According to G. N. Bishop's data, 3. to. results from the weak, but often following one by one irritations of the pain receptors transferring impulses on fibers C i.e. on those which carry rather slowly out excitement. There is a basis to assume that this feeling is perceived by the nervous receptors which are stuffed up in epidermis. The question of participation in developing of an itch of century of N of page, its sympathetic part, and also of a role of a histamine, serotonin and adrenaline finally is not solved yet. According to Rotman's data (S. Rothman, 1939), the itch can be caused also on desimpatizirovanny sites of skin.

A clinical picture

Clinically distinguish an itch generalized and localized. Current variously: from a single bad attack to long, months and years of the proceeding itch. Quite often for calm of an itch people resort to friction, stroking, pressure or warming of the pruritic site of skin, etc. Having as a result combed at an intensive and persistent itch on skin the linear, covered with bloody crusts excoriations which are quite often complicated by a piokokkovy infection are formed (see. Pyoderma ).

Allocate versions generalized 3. to. The senile itch (pruritus senilis) is connected with age changes of skin — atrophic processes in epidermis, grease and sweat glands, hair follicles and a derma, and also with the phenomena of atherosclerosis; it is more often observed at men 60 — 70 years in the form of attacks preferential are more senior at night.

The seasonal itch arises in the spring and in the fall more often at persons with the phenomena of vegeto-vascular dystonia. The so-called high-rise itch develops at some people at rise on height of 8000 — 10 000 m and more and is one of symptoms hypobaropathy (see); 3. to. can also arise at compressed-air disease (see); in connection with sharp difference of barometric pressure.

The localized itch most often arises in the field of an anus (pruritus ani) and generative organs (pruritus genitalium).

Pruritus ani is observed almost only at men, often is complicated by painful cracks, a streptococcal or barmy intertrigo, furuncles, a hydradenitis. Locks, hemorrhoids, worms (pinworms) can be its reasons; the itch sometimes complicates a proctitis, prostatitis, a vesiculitis, especially at non-compliance with rules of hygiene. High proteolytic activity mucous separated at a proctitis, a sigmoiditis that causes the persistent nature of a proctal itch is noted; assume also possible communication with disturbance of secretion of apocrine sweat glands.

Pruritus genitalium is observed preferential at women in external genitals [an itch of a vulva (pruritus vulvae)], is more rare — in a vagina. Are the reasons bleach, a trichomoniasis, irritant action of urine at diabetes, gout, endocrine frustration (a dysmenorrhea, a climax), inflammatory diseases of generative organs, Candidiasis, sexual neurosises, and also in some cases (is more often at girls) — pinworms. The itch in a clitoris quite often is one of early symptoms of cancer of generative organs. During pregnancy, especially in the second half, 3 can be observed. to. as display of toxicosis (see. Toxicoses of pregnant women ).

The diagnosis

First of all it is necessary to exclude parasitic diseases — mange (see), pediculosis (see. Louses ). Etiol, the diagnosis is made on the basis of careful poll, a wedge, and laboratory inspection of the patient.


Sedatives, intravenous injections of 10% of solution of calcium chloride, sodium thiosulphate, novocaine. Appointment nicotinic to - you, vitamin B is recommended 1 , antihistaminic drugs (Dimedrol, Pipolphenum, Suprastinum, tavegil, etc.). The good effect is rendered by a hydrotherapy — heat baths, souls, sea bathings, sulfur, radonic baths. In some cases there can be useful a suggestive therapy, an electrosleep. At a senile itch purpose of drugs of iodine, sex hormones is recommended (Testosteroni propionas, etc.). The patient suffering 3. to., it is necessary to avoid the irritating food, alcohol, strong tea, coffee. Outwardly apply antipruritic means — menthol (0,5 — 1%), salicylic to - that (1 — 2%), carbolic to - that (2 — 5%), etc. (in the form of water or spirit solutions, the shaken-up mixes), the cooling and corticosteroid ointments (Synalarum, Ftorokortum, Ultralanum, Dermosolonum, Hyoxysonum, etc.). At an itch of an anus and generative organs, in addition to treatment of the main disease, daily washings, use of toilet paper, sedentary heat baths with potassium permanganate, and also use of antipruritic outside means in the form of cream, paste are recommended, to the shaken-up suspension containing antihistaminic drugs, anaesthesin, menthol, phenol and other antipruritic means in concentration of 1 — 2%. Appoint microclysters from 0,5 — 1% solution of colloid silver or protargol (100 — 150 dm) to a course 12 — 15, candles with corticosteroids. In especially persistent cases novocainic blockade of a sexual nerve is shown.

The forecast

At identification of the reasons, defiant 3. to., and their elimination the itch stops. At a heavy hron, a current 3. to., when it is not possible to establish etiol, the factor, symptomatic means, observance of a diet and personal hygiene considerably facilitate a condition of the patient.

Bibliography: Berenbeyn B. A. Pruritic dermatosis (Neurodermatoses), M., 1971; Dyshko A. S. Itch (Experimental clinical trials), M., 1962, bibliogr.; Torsuyevn. And. ides of river. Allergic pruritic dermatosis, Kiev, 1973; Private allergology, under the editorship of A. D. Ado, M., 1976.

S. T. Pavlov.