A 45-year-old man with occipital headache lasting 2 days was admitted to our department. Urgent brain computed tomography and neurological examination were unremarkable. His clinical history revealed a renal transplantation 15 years before for glomerulonephritis followed by immunosuppressant therapy (steroids, ciclosporin, mycophenolate mofetil). Basal creatinine level was increased by 1.9 mg/dL (normal range 0.8-1.3). Because of persistence of the headache, a brain magnetic resonance imaging (MRI) was performed. This revealed a left intracranial vertebral artery dissection (VAD) without ischemic lesions (Figure A–D). Extensive laboratory studies proved normal, including screening for systemic autoimmune disorders and thrombophilic conditions. Cardiological evaluation (transthoracic echocardiogram, carotid duplex sonography, and 24-hour blood pressure measurement) and renal duplex sonography were unremarkable. No cervical traumas or manipulations were reported. A therapy with antiplatelets was started and the patient was discharged after 3 days. His headaches progressively resolved over subsequent months. Follow-up MRI, 60 days later, demonstrated complete VAD resolution (Figure E–F). COMMENT Cervical-artery dissections are defined by the presence of a mural hematoma located in the arterial wall. Generally the dissections have been reported to occur in the internal carotid artery, although they can also involve the vertebral artery. Many risk factors have been suggested, including traumas or manipulation to the neck, migraine, infection, hyperhomocysteinemia, and polymorphism of methylenetetrahydrofolate reductase gene. The presence of an underlying arteriopathy, however, may play a role in the VAD development. Headache and neck pain are common and suggestive symptoms of VAD and sometimes may represent the only clinical manifestation. Our patient presented with isolated occipital headache but without common risk factors for VAD. His clinical history included, however, 2 other significant conditions, both of which may induce vessel wall dysfunction: impaired renal function and prolonged use of immunosuppressant drugs. Renal failure is associated with cerebral small vessel disease while immunosuppressant drugs are responsible for vascular damage in animal model of coronary vessels. It is probable that both of these conditions contributed to VAD developing in this case. Clinicians should be aware that VAD may be responsible of new-onset and unexplained headache especially in patients with any vascular risk factor. From the Department of Neurology, Catholic University of Sacred Heart, Rome, Italy (M. Luigetti, P. Profice, F. Pilato, G. Della Marca, A. Broccolini, R. Morosetti, G. Frisullo, and V. Di Lazzaro); Don Carlo Gnocchi Onlus Foundation, Italy (A. Broccolini and R. Morosetti); Institute of Radiology, Catholic University of Sacred Heart, Rome, Italy (T. Tartaglione). ISSN 0017-8748 doi: 10.1111/j.1526-4610.2010.01744.x Published by Wiley Periodicals, Inc. Headache © 2010 American Headache Society