Pruritus or itching can be defined as a cutaneous sensation leading to the desire to scratch. Scratching in response to itch is a spinal reflex which can be modulated by the brain. Free nerve endings in the skin act as itch receptors. Following their activation, slowly conducting C nerve fibres (which also transmit pain sensation) transmit the itch sensation to the spinal cord and via the lateral spinothalamic tract to the thalamus. Additional impulses may be carried by rapidly conducting delta fibres and by the activation of adjacent neurones within the sensory relay areas of the cord. Pharmacological mediators (e.g. opioid peptides) in the periphery or within the central nervous system influence the perceived quality of itch.
KeywordsPrimary Biliary Cirrhosis Mycosis Fungoides Geriatric Medicine Dermatitis Herpetiformis Chronic Venous Insufficiency
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