Like neuropathic pain, neuropathic itch is still poorly understood despite fundamental advances in understanding the mechanisms of itch in the normal nervous system. Neuropathic itch and pain are signaling abnormalities – the source of the problem is not where the symptoms are felt. Many physicians including neurologists are unaware that neurological problems alone can cause chronic itch. Current treatment recommendations include local or systemic administration of inhibitors of neuronal excitability (especially local anesthetics) and barriers to reduce scratching. Treating neuropathic itch is difficult antihistamines, corticosteroids, and most pain medications are largely ineffective. The most common location is on the face (trigeminal trophic syndrome). Rare patients whose lesion causes sensory loss as well as neuropathic itch can scratch deeply enough to cause painless self-injury. Neuropathic itch is a potent trigger of reflex and volitional scratching although this provides only fleeting relief. Central nervous system lesions affecting sensory pathways, including strokes, multiple sclerosis, and cavernous hemangiomas can cause central itch. These include shingles (particularly of the head or neck), small-fiber polyneuropathies, radiculopathies (e.g., notalgia paresthetica and brachioradial pruritis) and diverse lesions of the trigeminal nerve, root, and central tracts. The same neurological illnesses that cause neuropathic pain can also or instead cause itch. All neurological disease categories have been implicated and neurological causes should be considered for patients with otherwise-unexplained itch. The cellular and molecular mechanisms are still unknown. Chronic itch can be caused by dysfunctions of itch-sensing neurons that produce sensory hallucinations of pruritogenic stimuli.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |