Allodynia is a type of sensory impairment associated with neuropathic pain conditions
. It describes a condition in which a stimulus that is normally not painful causes pain sensations. For example, when someone has allodynia, a light touch may be interpreted by the brain as painful.
More about how we feel pain.
Someone who has reflex sympathetic dystrophy
(RSD) may feel pain when they put their hands under running water. Because running water normally does not cause pain, this is an example of allodynia.