Treatment of itchy skin

Lack of knowledge of the pathophysiology of pruritus explains the difficulty in selecting an effective treatment option. The primary focus of any therapeutic measures in case of pruritus should be the treatment of the underlying disease. In addition, provocative factors such as dry skin, contact with irritants, measures to degrease the skin (alcohol dressings), consumption of certain foods (alcohol, spices), and temperature changes in the environment should be eliminated. Long-term use of potential contact allergens (antihistamines, local anesthetics) should be avoided, as well as doxepin (potential antihistamine), which has been successfully used locally in atopic dermatitis, but due to its chemical structure and increased T-cell activity, has a high degree of sensitization.

Accompanying measures (avoiding stress, autogenic training, help from a psychologist, correction of the influence of the psychosocial environment; appropriate clothing, showering, wet wraps; if necessary, lubricating the skin with urea, which has a direct antipruritic effect) can alleviate itching.

Depending on the underlying disease, it is advisable to include corticosteroids, anesthetics (phenol, camphor, menthol, polidocanol), clioquenol, resorcinol, tar in appropriate bases in the prescription. Transcutaneous electrical neurostimulation or acupuncture can be used as a supporting measure. New in the treatment of itching is the use of capsaicin. Capsaicin is an alkaloid extracted from the paprika plant (pepper).

The treatment of itching should be based on three aspects. First, there is the causal approach, in which the specific pathogen is eliminated. If this is not possible or not possible quickly enough, one can try to alleviate the symptoms, for example, by influencing the release of itch-mediating mediators. If this also fails, one can try to modulate the factors that worsen the itching in order to make the symptoms tolerable.

Causal therapy can successfully eliminate the symptoms of acute and moderate forms of itching, if the causes are clear. Thus, in most cases it is possible to eliminate the allergen causing acute urticaria or other allergic exanthema (medicines; allergens in foods; 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 agents externally or internally. In some patients with malignant tumors as a cause of itching, successful surgical or medical treatment leads to the disappearance of symptoms with their return in case of relapses. In lymphoproliferative diseases, according to recent reports, both itching and pain itself respond to alpha-interferon. Successful treatment of other internal diseases (chronic renal failure, liver disease, diabetes mellitus) also leads to the alleviation or elimination of itching. In case of itching with neurotic or mental disorders, psychotherapy with elimination of stress factors or treatment with tranquilizers, hypnosis or acupuncture can be successful.

In clinical practice, in a number of diseases and in numerous pathological processes with itching of unknown origin, it is impossible to eliminate the underlying disease or avoid the pathogen. Here begins the medical art of alleviating itching either by influencing the action of itching mediators on the target organ, free nerve endings, or by modulating the transmission of itching along peripheral and central nerve pathways.

Histamine is the only reliably identified transmitter of itching in experimental and pathological conditions. Therefore, in most mast cell diseases, itching and papular rashes can be treated with antihistamines, but reflex redness is less successful. Older antihistamines, which have a central sedative effect, differ little in their action on itching and vesicular rashes from newer non-sedative drugs. Primarily histamine-mediated itching occurs in acute and some chronic urticaria, as well as in some forms of physical urticaria, such as mechanical and pigmented urticaria, in most patients with cholinergic urticaria. Itching during wound healing, after insect bites and contact with plants (eg, nettles) is caused by mast cells or histamine.

Non-sedating antihistamines completely suppress itching in 70% of patients with chronic urticaria, and the remaining patients show improvement. In patients with eczema, most well-controlled studies show no response to various antihistamines. Antihistamines, which also affect the release of mediators from mast cells and the migration of eosinophils, show, on the contrary, some effectiveness in atopic dermatitis (cetirizine, loratadine). In general, antihistamines are classified as low or ineffective in the treatment of itching in eczema diseases. Local antihistamines act to a limited extent in these same diseases, and should be avoided in children due to potential systemic side effects (contact sensitization) when applied to large areas.

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

Photochemotherapy (PUVA) can reduce pruritus in some mast cell and inflammatory diseases. Examples include prurigo nodularis, paraneoplastic pruritus, urticaria pigmentosa, and hypereosinophilic syndrome. In photourticaria, UV therapy is used more in the sense of "hardening" the skin or inducing tolerance. The effect of UV therapy is short-lived, lasting only slightly longer than the duration of treatment, and PUVA itself can cause pruritus in some patients.

Cyclosporine A is effective even in small doses (5 mg/kg of body weight per day) in eczema, urticaria, atopic dermatitis, alleviating itching, but it is also not perfect, since relapse occurs quickly after discontinuation of the drug. In addition, it is a potentially nephrotoxic agent.

In intrahepatic cholestasis with a decrease in endogenous bile acids in the serum, in particular, cholic acid, as a result of treatment with cholestyramine or ursodeoxycholic acid, chronic itching together with alkaline phosphatase is significantly reduced. According to the latest data, in adults and children, cholestatic itching responds well to rifampicin, although its high degree of side effects, possible cross-effects with other drugs and the relatively high cost of therapy should be taken into account. The relatively good effect of cholestyramine is mentioned, the effect of which can be further enhanced by the simultaneous use of UV therapy. Morphine antagonists (naloxone, nalmefene) and plasmapheresis are moderately helpful. Surgical measures (drainage of bile fluid - stoma, liver transplantation if indicated) dramatically improve the symptoms of itching.

In the treatment of itching, in addition to general modulating measures, it is important to reduce inflammation. It does not matter how this is done: by using external glucocorticoids or, in very severe cases, by systemic cyclosporine therapy. It is important to reduce T-cell infiltration with 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, urea is fundamentally indicated, as well as tar, which softens itching and weakens the hyperproliferation of keratinocytes and lichenification. Itching in acute inflamed skin and in the chronic state of atopic dermatitis should be treated differently. Subacute stages can be treated with UV radiation, but sometimes UVA irradiation leads to suppression of inflammation and itching in the acute stage as well. If antihistamines are used, then mainly in the evening and only sedatives.

Patients with skin itching are recommended to treat concomitant diseases. A diet is prescribed with the exclusion of obligate and individual trophoallergens: egg white, meat broth, chocolate, spices, sweets, alcohol; the use of table salt, smoked and canned products is limited. Fermented milk and plant products are indicated.

As symptomatic therapy, sedatives (valerian, motherwort, tranquilizers); antihistamines (suprastin, fenkarol, diazolin, erolin, loratadine); desensitizing (hemodez, calcium preparations, sodium thiosulfate); anesthetics (0.5% novocaine solution, 1% trimecaine solution); enterosorbents (belosorb, activated carbon, polysorb, polyphepan) can be used.

Local therapy. Topical use includes powders, alcohol and water solutions, shaken suspensions, pastes, and ointments. The antipruritic effect depends on the dosage form. The following agents of various compositions have a local antipruritic effect: 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% citric acid solutions; infusions of chamomile and succession herb. If there is no effect, the itchy areas can be lubricated for a short time with corticosteroid ointments (locoid, elokom, advantan, flucinar, fluorocort).

Antipruritic action is provided by hydrogen sulphide baths; baths with decoction of oak bark, succession (50-100 g), bran (300-500 g per bath); sea bathing; baths with pine extract, sea salt, starch. Water temperature 38°C, duration of procedure 15-20 minutes, 10-20 baths per course.

Hypnosis, electrosleep, acupuncture, laser puncture, magnetic therapy, UHF therapy, biorhythm reflexotherapy, and hydrocortisone phonophoresis are shown.

Retinoids in patients with atopic predisposition may provoke itching instead of reducing it. However, in lichen planus, lichen sclerosus and lichen atrophicus, itching disappears within a few days even at low doses (etretinate or isotretenoin 10-20 mg per day). Skin manifestations, on the contrary, do not necessarily respond to the drug. The same is true for topical treatment with 2% estrogen or testosterone cream.

In treating widespread perianal itching, the cause of the disease should first be eliminated and the hygiene of the anal area should be normalized. Irritants should be avoided in the diet: citrus fruits and spices. Then injections of 5% phenol in almond oil into the subcutaneous tissue of the distal anus are recommended; in 90% of cases, this method provides recovery.

If the cause of itching is unknown or the above therapeutic options have been exhausted, itching relief measures can be used. This includes, first of all, regular skin care with oily external agents, especially in old age. In patients with aquagenic itching, this is the treatment of choice.

The attack of itching can be significantly reduced by the patients themselves through autogenic training. Patients with itching should be asked how they usually wash themselves. Too frequent washing with hot water, excessive use of soap leads to a decrease in natural fat lubrication and dry skin, which favors itching. Warm dry air from heating devices and the warmth of bed linen are factors that worsen the patient's condition. Patients often report relief from night attacks of itching after taking a cold shower. It is also necessary to additionally use fat lubrication on the skin.

In summary, itching is controlled by modern pharmacological agents only to a limited extent. Exceptions are urticarial reactions that respond well to antihistamines and recently discovered therapeutic options for treating chronic itching in renal failure and liver disease. Itching in chronic eczema responds to corticosteroids, but the side effects are unacceptable for long-term therapy. In general, finding the cause of itching is an important basis for successful targeted therapy. In addition, itching in most patients can at least be alleviated by skillful use of currently available therapeutic methods and agents.