Numb chin syndrome (NCS) is a rare but important clinical symptom and sign. It describes a condition presenting as anaesthesia, paraesthesia, or dysesthesia over the chin, which is usually unilateral. The condition manifests spontaneously with no history of trauma, infection or obvious odontogenic cause. NCS is a clinically important finding as it may be the primary manifestation of Multiple Sclerosis (MS) or sign of systemic malignancy.
If there is no recent history of trauma or obvious dental cause the patient should be referred to a neurologist for evaluation. I personally have had a patient with NCS in the form of extremely painful burning sensation=dysesthesia. It was quickly discovered to be a metastatic tumor putting pressure on the IAN. She survived for about a year after it’s discovery. Unfortunately by the time a NCS occurs, if it is found to be related to metastatic cancer, it is usually too late to do very much.