Treatment of skin itching

Lack of knowledge of the pathophysiology of itching explains the difficulty in selecting an effective therapy option. On the first place of any therapeutic measures in case of itching should be the treatment of the underlying disease. In addition, provocative factors, such as dry skin, contact with irritants, skin degreasing (alcohol bandages), certain foods (alcohol, spices), as well as temperature changes in the environment should be eliminated. Long-term use of potential contact allergens (antihistamines, local anesthetics), as well as doxepin (a potential antihistamine), which has been successfully applied topically with atopic dermatitis, should be avoided, but has a high degree of sensitization due to its chemical structure and the increase in T-cell activity.

Accompanying measures (avoidance of stress, autogenic training, psychologist's help, correction of the influence of the psychosocial environment, appropriate clothing, showering, wet wraps, if necessary, fatty skin lubrication with urea, which has a direct anti-pruritic effect) can soften the itching.

Depending on the underlying disease, it is advisable to include corticosteroids, anesthetics (phenol, camphor, menthol, polidocanol), clyvenols, resorcinol, tar in appropriate bases in the formulation. As a supportive measure, transcutaneous electric neurostimulation or acupuncture can be used. New in the treatment of pruritus is the use of capsaicin. Capsaicin is an alkaloid extracted from a paprika plant (pepper).

In the treatment of pruritus, three aspects should be considered. At first, it is a causal (causal) approach, in which a specific causative agent of the disease is eliminated. If this is not possible or perhaps not fast enough, you can try to soften the symptoms, affecting, for example, the release of mediator-mediated itching. If this fails, you can try to modulate the factors that worsen the itch to make the symptoms tolerable.

Causal therapy can successfully eliminate the symptoms of acute and medium-length forms of itching, if the causes causing it are clear. Thus, in most cases it is possible to eliminate the allergen causing acute urticaria or other allergic exanthema (medicines, allergens in food, pseudoallergens such as aspirin and food additives, physical irritants such as cold, pressure and UV rays). The same applies to contact allergens. Parasites can also be eliminated by applying appropriate means externally or orally. In some patients with malignant tumors, as a cause of pruritus, successful surgical or therapeutic treatment results in the disappearance of symptoms with their return upon relapse. With lymphoproliferative diseases, according to the latest reports, both the itching and the pain themselves react to alpha interferon. Successful treatment of other internal diseases (chronic renal failure, liver disease, diabetes) also leads to the easing or elimination of itching. When itching with neurotic or psychiatric disorders, psychotherapy with the elimination of stress factors or treatment with tranquilizers, hypnosis or acupuncture is successful.

In clinical practice, with a variety of diseases and with numerous pathological processes with pruritus of an unknown nature, it is impossible to eliminate the underlying disease or to avoid the pathogen. Here begins the medical art to soften the itch, either by affecting the effect of itch mediators on the target organ, free nerve endings, or by modulating the transmission of itching along peripheral and central nervous pathways.

Histamine in experimental and pathological conditions is the only reliably identified itch transmitter. Therefore, in most diseases caused by mast cells, itching can be treated and papular rashes with antihistamines, but less successfully - reflex reddening. Old antihistamines, which have a central sedative effect, in their effects on itching and blistering rashes, differ little from new non-sedative drugs. Primarily due to histamine itching occurs with acute and some chronic urticaria, as well as some forms of physical urticaria, for example, with mechanical and pigmentary urticaria, in most patients with cholinergic urticaria. Itching in the treatment of wounds, after insect bites and contact with plants (for example, nettle) is caused by mast cells or histamine.

Non-active antihistamines in 70% of patients with chronic urticaria completely suppress the itching, and in the remaining patients there is an improvement. In patients with eczema in most studies with good control there is no response to various antihistamines. Antihistamines, which also affect the release of mediators from mast cells and the migration of eosinophils, demonstrate, on the contrary, a certain efficacy in atopic dermatitis (cetirizine, loratadine). In general, antihistamines are classified in the treatment of pruritus in the case of example diseases as little or ineffective. Local antihistamines with these same diseases operate on a limited scale, and in the treatment of children they should be avoided because of potential systemic side effects (contact sensitization) when applied in large areas.

The weak effect of antihistamines in many inflammatory dermatoses contrasts with the rapid reaction of pruritus to glucocorticoids, and along with the symptoms of pruritus, other parameters of inflammation are suppressed. In the absence of contraindications, corticosteroids are used systemically for acute diseases (acute urticaria, acute contact eczema). In chronic diseases, on the contrary, they are contraindicated, except for short-term treatment of exacerbations.

Photochemotherapy (PUVA) can reduce itching in certain diseases caused by mast cells and inflammation. As an example, nodular prurigo, paraneoplastic pruritus, pigmentary urticaria and hypereosinophilic syndrome are used. With light urticaria UV therapy is used more in the sense of "hardening" of the skin or induction of tolerability. The effect of UV therapy is short, it only slightly exceeds the duration of treatment, and in addition, the PUVA-therapy itself in some patients can cause itching.

Ciclosporin A works already in small doses (5 mg / kg of weight per day) with eczema, urticaria, atopic dermatitis, softening the itching, but it is also not flawed, because after the drug is quickly relapsed. In addition, it is potentially a nephrotoxic agent.

With intrahepatic cholestasis, when the endogenous bile acids in the serum, in particular cholic acid, are reduced, as a result of treatment with cholestyramine or ursodeoxycholic acid, chronic itching along with alkaline phosphatase is significantly reduced. According to recent data, cholesteric itching responds well to adults and children with rifampicin, although it should be taken into account its high side effect, possible cross-treatment with other medicines and the relatively high cost of therapy. Mention is made of the relatively good effect of cholestyramine, the effect of which can still be increased by the simultaneous use of UV therapy. Morphine antagonists (nalaxone, nalmefene) and plasmapheresis are moderately well helped. Operative measures (removal of bile fluid - stoma, liver transplantation with appropriate indications) dramatically improve the symptoms of itching.

In the treatment of pruritus, in addition to general modulating measures, inflammatory reduction is important. However, it does not play a decisive role, as it will be: by using external glucocorticoids or, in very severe conditions, by systemic therapy with cyclosporine. It is important to reduce T-cell infiltration with the subsequent release of inflammatory mediators into the epidermis. Xerosis in atopy is another aspect of treatment and requires the use of substances that bind water. Therefore, in principle, urea, as well as tar, which softens the itch and weakens the hyperproliferation of keratinocytes and lichenification. Itching should be treated differently in case of acute inflamed skin and chronic condition of atopic dermatitis. Subacute stages can be treated with UV irradiation, but sometimes UVA, -reduction leads to suppression of inflammation and itching and in the acute stage. If antihistamines are used, then mostly in the evening and only a sedative type.

Patients with dermal itching are recommended therapy of concomitant diseases. Assign a diet with the exception of obligate and individual trophoallergens: egg white, meat broth, chocolate, spices, sweets, alcohol; restrict the use of table salt, smoked and canned products. Milk-sour, vegetative products are shown.

As a symptomatic therapy, sedatives can be used (preparations of valerian, motherwort, tranquilizers); antihistamines (suprastin, phencarol, diazolin, erroline, loratadine); desensitizing (gemodez, calcium preparations, sodium thiosulfate); anesthetics (0.5% solution of novocaine, 1% solution of trimecaine); enterosorbents (whitener, activated carbon, polysorb, polyphepan).

Local therapy. Locally applied powders, alcohol and aqueous solutions, agitated suspensions, pastes, ointments. The antipruritic effect depends on the dosage form. Antipruritic local effect has the following means of different compositions: 0.5-2.0% menthol; 1-2% thymol; 1-2% anesthesin; 1-2% phenol (carbolic acid); alcohols (1-2% resorcinol, 1-2% salicylic, camphor, 30-70% ethyl); 1-2% solutions of citric acid; infusions of chamomile, herbaceous alternatives. In the absence of the effect, itchy areas can be briefly lubricated with corticosteroid ointments (lokoid, elok, advantan, flucinar, fluorocort).

An antipruritic effect is produced by hydrogen sulphide baths; baths with decoction of oak bark, turns (50-100 g), bran (300-500 g per bath); sea bathing; baths with pine extract, sea salt, starch. The water temperature is 38 ° C, the procedure lasts 15-20 minutes, for a course of 10-20 baths.

Hypnosis, electrosleep, acupuncture, laseropuncture, magnetotherapy, EHF-therapy, biorhythmoreflexotherapy, phonophoresis of hydrocortisone are shown.

Retinoids in patients with atopic predisposition may provoke itching instead of reducing it. However, with red flat lichen, sclerotic and atrophic lichen, the itching disappears for several days even at low doses (etretinate or isotretenone 10-20 mg per day). Skin manifestations, on the contrary, do not necessarily react to the drug. The same is true for topical treatment with 2% estrogen or testosterone on a cream basis.

In the treatment of widespread perianal pruritus, the cause of the disease should first be eliminated and the hygiene of the anal region should be normalized. In the diet avoid irritating substances: citrus and spices. Next, injections of 5% phenol in almond oil into the subcutaneous tissue of the distal anus are recommended; in 90% of cases this method gives a recovery.

If the cause of the itch is not known or the above therapeutic possibilities are exhausted, itching measures can be applied. This includes, above all, regular skin care with oily external means, especially in old age. In patients with aquatic itching, this is a means of choice.

A seizure attack can be significantly reduced by the patients themselves through autogenous training. Patients with itching should be interviewed as they are used to washing. Too frequent washing with hot water, excessive use of soap leads to a decrease in the natural fatty grease and dry skin, which is conducive to itching. Warm dry air from heating appliances and warm bedding are factors that worsen the patient's condition. Patients often report relief of nocturnal attacks of pruritus after taking a cold shower. It is also necessary to additionally use the grease on the skin.

Summarizing the above, we can say that itching is controlled by modern pharmacological agents only limited. The exceptions are well-responding to antihistamines, urticarial reactions and the recently discovered therapeutic possibilities of treating chronic pruritus in renal failure and liver diseases. Itching for chronic eczema reacts to corticosteroids, but side effects are unacceptable for long-term therapy. In general, the search for the cause of pruritus is an important basis for successful targeted therapy. In addition, the itch in most patients can be at least facilitated by skillful application of the currently available therapeutic methods and means.