Posttraumatic hemicrania continua.

Hemicrania continua is a rare, benign headache disorder characterized by a low-level baseline hemicranial headache with superimposed exacerbations of more severe pain. Exacerbations last from minutes to days and may be associated with ipsilateral autonomic features such as ptosis, miosis, conjunctival injection, lacrimation, or rhinorrhea; when present, these features tend to be less pronounced than those seen with cluster headache. Response to treatment with indomethacin, in doses ranging from 25 to 300 mg per day, has been deemed a sine qua non of diagnosis. To date, in the majority of instances, hemicrania continua appears to have arisen de novo, without any identifiable trigger. We report four patients in whom the onset of hemicrania continua was temporally linked to head trauma.