Dysesthésie

Dysesthesia is an unpleasant, abnormal sense of touch. Its etymology comes from the Greek word "dys," meaning "bad," and "aesthesis," which means "sensation" (abnormal sensation). It often presents as pain but may also present as an inappropriate, but not discomforting, sensation. It is caused by lesions of the nervous system, peripheral or central, and it involves sensations, whether spontaneous or evoked, such as burning, wetness, itching, electric shock, and pins and needles. Dysesthesia can include sensations in any bodily tissue, including most often the mouth, scalp, skin, or legs. It is sometimes described as feeling like acid under the skin. Burning dysesthesia might accurately reflect an acidotic state in the synapses and perineural space. Some ion channels will open to a low pH, and the acid sensing ion channel has been shown to open at body temperature, in a model of nerve injury pain. Inappropriate, spontaneous firing in pain receptors has also been implicated as a cause of dysesthesia. People with dysesthesia can become incapacitated with pain, despite no apparent damage to the skin or other tissue. Dysesthesia can generally be described as a class of neurological disorders. It can be further classified depending on where it manifests in the body, and by the type of sensation that it provokes. Cutaneous dysesthesia is characterized by discomfort or pain from touch to the skin by normal stimuli, including clothing. The unpleasantness can range from a mild tingling to blunt, incapacitating pain. Scalp dysesthesia is characterized by pain or burning sensations on or under the surface of the cranial skin. Scalp dysesthesia may also present as excessive itching of the scalp. Occlusal dysesthesia, or "phantom bite," is characterized by the feeling that the bite is "out of place" (occlusal dystopia) despite any apparent damage or instability to dental or oromaxillofacial structures or tissue. Phantom bite often presents in patients that have undergone otherwise routine dental procedures.