Почему чешется кожа: особенности диагностики и лечения зуда

Itching is a symptom that can cause significant discomfort and is also one of the most common reasons for consulting a dermatologist.

Itching results in scratching that can cause inflammation, skin degradation and possible secondary infection.

There are many factors that can cause itching, which include dermatological and systemic diseases.

On estet-portal.com read what can cause itching, what is the pathophysiology of this process, as well as how to diagnose and treat itching.

Pathophysiology of pruritus

Itching can be caused by a variety of irritants, including light touch, vibration, and wool fibers.

There are a number of chemical mediators and various mechanisms by which the sensation of itching occurs.

Specific peripheral sensory neurons mediate the sensation of itching.

These neurons are different from those that respond to light touch or pain; they contain the MrgA3 receptor, the stimulation of which causes an itch sensation.

  • Itching mediators

Histamine is a well-known mediator of itching. It is synthesized and stored in the mast cells of the skin and released in response to various stimuli.

Other mediators (e.g. neuropeptides) can either cause the release of histamine or act as itching agents themselves.

This explains why pre-administered antihistamines for itching are not always effective.

Opioids cause central pruritus.

  • Mechanisms of itching

There are 4 mechanisms of itching:

  1. Dermatological: this mechanism is usually caused by inflammatory or pathological processes (eg urticaria, eczema);
  2. Systemic: this mechanism is associated with diseases of organs other than the skin (e.g. cholestasis);
    3. Neuropathic
  3. : this mechanism is associated with CNS or peripheral nervous system disorders (eg, multiple sclerosis);
    4. Psychogenic:
  4. this mechanism is associated with mental illness.
    5. Intense itching leads to scratching of the skin and excoriations, which in turn can cause secondary skin conditions (eg, inflammation, irritation, infection), which can lead to increased itching due to breakdown of the skin barrier

ra. Although scratching may temporarily reduce the sensation of itching by activating inhibitory neuronal circuits, it also leads to increased itching at the brain level, exacerbating the itching-scratch cycle.

How allergic dermatosis manifests itself: features of the clinical picture Itching etiology: why patients itch

Itching may be a symptom of a primary skin disease or, less commonly, a systemic disease. In addition, some medicines can cause itching.

The most common

dermatological causes of

itching include:

dry skin;
  • atopic dermatitis (eczema);
  • contact dermatitis;
  • fungal skin infections.

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Systemic disorders

are less likely to cause itching than skin conditions, but some of the more common causes include:

allergic reaction (e.g. to food, drugs, and bites);
  • cholestasis;
  • chronic kidney disease;
  • hyperthyroidism;
  • hypothyroidism;
  • diabetes;
  • iron deficiency.
    • Some medications can cause itching as an allergic reaction or by directly triggering the release of histami

on.

What internal diseases can cause itching Examination of a patient with itching

In the history of the disease should be determined:

time itching started;
  • source location;
  • current;
  • duration;
  • nature of itching (eg, nocturnal or daily, intermittent or constant, seasonal);
  • presence of a rash.
    • To diagnose the cause of itching, you should find out what medications the patient is taking and what care products they use.
The physical examination begins with a review of the clinical presentation of signs of jaundice, weight loss, or weight gain.

A thorough examination of the skin should be performed, taking into account the presence, morphology, extent and distribution of lesions.

On examination, signs of secondary infection should also be noted.

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in Telegram! Treatment of pruritus of various etiologies

The main disease is treated first, and supportive therapy is prescribed in parallel:

diet;
  • skin care;
  • topical preparations;
  • systemic medicines.
    • Itching from any cause benefits from the use of cold or warm (but not hot) water when bathing, mild or moisturizing soaps, limited duration and frequency of bathing, humidification of dry air, and the choice of natural light clothing.

Topical lotions or creams that contain camphor and/or menthol, pramoxine, capsaicin, or corticosteroids help relieve itching.

Corticosteroids are effective in relieving itching caused by inflammation, but should be avoided in conditions that do not show signs of inflammation.

Topical benzocaine, diphenhydramine and doxepin should be avoided because they may sensitize the skin.

Systemic preparations to reduce itching – they are antihistamines.

Physical agents that may be effective for itching include ultraviolet phototherapy.

Helping the Dermatologist: European Guidelines for Chronic Pruritus