The mechanism of itching in the human body
*The physiological and chemical mechanism of pruritus is mainly involved in the transmission and response of nerve endings and the brain to the sensation of itching. In addition to physical and chemical stimuli, the causes of itching include pathological factors such as bile acid accumulation, neurotransmitter abnormalities, increased histamine release, impaired blood circulation, and dysfunction of the immune system. Traditional Chinese medicine understands that itching is mainly related to "wind".
1. Physical or chemical stimuli.
When subjected to a physical or chemical stimulus, free nerve endings or unmyelinated nerve networks are stimulated, and this stimulation is transmitted to the brain, resulting in an itchy sensation. Both itch sensation and pain sensation are distributed in a punctate pattern on **, and the density is similar, but the transmission and response mechanism of itch sensation is different from that of pain sensation.
2. Choleate accumulation.
When the liver's metabolic capacity decreases, it leads to an increase in bile acid levels in the blood. These high concentrations of bile salts are deposited on ** and irritate sensory nerve endings, causing an itching sensation.
3. Neurotransmitter abnormalities.
Some neurological disorders or medications*** can cause an imbalance in neurotransmitters, which can trigger itching symptoms. For example, in multiple sclerosis and Parkinson's disease, itching may occur due to abnormal neurotransmission due to neuronal damage.
Fourth, increased histamine release.
Certain food allergens or other external irritants can trigger the body to produce more histamine molecules. Histamine is a chemical that promotes vasodilation and increased permeability, which in turn leads to the occurrence of itching.
5. Blood circulation disorders.
For example, peripheral neuropathy caused by poor blood sugar control in diabetic patients, or varicose veins of the lower limbs caused by the presence of atherosclerosis in the elderly may cause local circulation to be poor, thus inducing itching symptoms.
6. Immune system dysfunction.
Pruritus in some patients is associated with autoimmune diseases, such as thyroiditis and lupus erythematosus, the cause of which is not yet known but may be related to a dysfunction of the immune system.