The neurology of itch

Abstract

Itch, or pruritus, is a common sensation, yet it is often treated lightly due to its usually transient nature. However, problems can arise once it becomes intense or prolonged, and treatment is ineffective. Itch generally affects diseased skin and accompanies systemic diseases; however, it can also be a reaction to allergens (mostly drugs) or have a psychogenic origin. Neurological itch is an itch that results from nervous system damage rather than issues with the skin. It affects non-diseased skin and arises as a result of dysfunction or damage to the neurons of the peripheral or the central nervous system. Its emergence can be influenced by metabolic, neurodegenerative, traumatic, infectious, autoimmune, and iatrogenic factors. Itch is accompanied by secondary symptoms including swelling, scrapes, excoriations or ulcerations, which result from the patient’s attempts to alleviate the symptoms. The diagnosis of itch is difficult and based on a detailed medical history and physical examination carried out in order to recognise the nature of the itch, which can also, in many cases, help find the most probable cause. There are no effective treatments for neurological itch. Management consists of a combination of patient education, physical therapy, psychotherapy, and attempts at a pharmacological treatment (antidepressants; antiepileptics − gabapentin and pregabalin; capsaicin; topical glucocorticosteroids).