Fiber neuropathy is a condition characterized by severe pain attacks that typically begin in the feet or hands. Those diagnosed with fiber neuropathy are unable to feel pain that is concentrated in a very small area, such as a pin prick, but do have an increased sensitivity to pain in general and experience pain from stimulation that typically would not cause pain. There may also be a reduced ability to differentiate between hot and cold, but these temperature changes may trigger pain attacks.
Some affected individuals may have urinary or bowel problems, episodes of rapid heartbeat, dry eyes or mouth, abnormal sweating, or a sharp drop in blood pressure.
Small Fiber Neuropathy. U.S. National Library of Medicine. https://ghr.nlm.nih.gov/condition/small-fiber-neuropathy