Carotid artery dissection is a frequent non-atherosclerotic cause of stroke in young adults. In up to 20% of cases it is bilateral or associated with vertebral artery dissection.1 Common clinical features include unilateral pain on the side of the dissection, signs of cerebral ischaemia, ear bruits, and Horner's syndrome,2 which is usually incomplete and sometimes transient.3 Horner's syndrome is thought to result from a lesion of the periarterial sympathetic plexus caused by the dissection.2 Rhinorrhoea and nasal congestion have not yet been reported as symptoms of spontaneous carotid artery dissection but have been seen in patients undergoing cranial base surgery.4 We here describe a patient with spontaneous bilateral carotid artery dissection in whom rhinorrhoea, nasal congestion, and headache were the first symptoms, which preceded the development of incomplete Horner's syndrome for several weeks.