A painful syndrome characterized by dull aching or throbbing, rather than paroxysms of pain, such as seen in trigeminal, glossopharyngeal, or postherpetic neuralgia, occurring in areas supplied by various nerve groups, including the fifth and ninth cranial nerves and the second and third cervical nerves. The distribution of atypical facial pain does not follow the established pathways of innervation of the major sensory nerves, however (i.e., trigeminal neuralgia). Attacks last from a few days to several months and often occur after dental care or sinus manipulation, but examination of the teeth, nose, sinuses, ears, and temporomandibular joints seldom reveals any abnormalities. A psychogenic or vascular etiology has been suggested.