Itching of the skin as a symptom of diseases of internal organs and skin

Types of itching

In the literature, the term “itch” refers to a sensation that causes a purposeful scratching reflex. In the scientific literature, itching is also referred to by the term "pruritus" (from Latin prurio – to scratch). This phenomenon is often one of the first symptoms of not only skin diseases, but also internal diseases, diseases of the nervous system, hormonal disorders, and even tumors. That is why itching is currently regarded as an "interdisciplinary symptom" and in some cases even isolated as a separate disease.

There is general (generalized) and local (localized) skin itching. Acute generalized is more often the result of food, drug allergies, reactions to cold, heat, etc. Generalized itching of the skin is often a symptom of serious diseases: diabetes mellitus, diseases of the gastrointestinal tract, kidneys, malignant neoplasms, etc.

Localized itching occurs most often in the scalp and anogenital area and is paroxysmal. The causes of the development of this phenomenon in the anal region are usually considered to be chronic inflammatory processes in the pelvic organs, infections, including helminthic infestations, etc. Long-term sensations are often complicated by the development of bacterial infection, candidiasis. Localized itching is also observed in the area of rashes in various skin diseases: psoriasis, atopic dermatitis, etc.

Frequency of itching in skin and systemic diseases

Itching that persists for more than 6 weeks is defined as chronic. Its frequency among the adult population is, according to research, 8-9%. Chronic phenomena are observed in various skin diseases (atopic dermatitis/neurodermatitis, eczema, prurigo, psoriasis, etc.) and systemic diseases.

Itching in various skin diseases

Mechanism of itching development

The mechanisms of itching development in chronic kidney diseases are not fully known. The role of metabolic disorders is assumed, as well as the involvement of opioid receptors in the process and increased dryness of the skin. Itching develops, as a rule, 2-3 months after the start of hemodialysis, in 25-50% of cases it is generalized, in other cases it is localized. As a rule, itching is most pronounced in the back and face area.

In liver diseases, itching is a very common symptom (observed in 80% of cases of cirrhosis of the liver, in 15% of all cases of viral hepatitis C). It usually begins in the area of the palms and soles, as well as in the area of clothing friction. It is characterized by its increase at night. Over time, the itching becomes generalized, while combing the skin brings almost no relief.

With endocrine pathology, for example, diabetes mellitus and hyperthyroid gland hyperfunction, itching may be accompanied by a burning sensation, tingling, “goosebumps". A lack of vitamin D, minerals, and iron also leads to the development of this phenomenon in some cases. With iron deficiency, “aquagenic itching" (upon contact with water) is often observed. As a rule, the restoration of normal levels of iron and minerals leads to the disappearance of any sensations within 2 weeks after the start of therapy.

Itching can be one of the symptoms of tumors and blood diseases. Possible mechanisms of its occurrence include toxic effects, allergic reactions to tumor components, and direct irritant effects on nerves and the brain (in brain tumors).

Systemic diseases that may be accompanied by itching

• Metabolic and endocrinological disorders: chronic renal failure, liver diseases, thyroid and parathyroid gland diseases, iron deficiency.
• Infectious diseases: HIV infection, parasitosis and helminth infestations.
• Blood diseases:true polycythemia, myelodysplastic syndrome, lymphoma.
• Neurological diseases: multiple sclerosis, neuropathy, tumors of the brain and spinal cord, postherpetic neuralgia.
• Psychosomatic and psychiatric disorders: depression, eating disorders, bipolar disorders.