For recurrent headaches, the following are noted: Age at onset Frequency of episodes Temporal pattern (including any relationship to phase of menstrual cycle) Response to treatments (including over-the-counter treatments) Review of systems should seek symptoms suggesting a cause, including Vomiting: Migraine or increased intracranial pressure Fever: Infection (eg, encephalitis, meningitis, sinusitis) Red eye and / or visual symptoms (halos, blurring): Acute angle-closure glaucoma Visual field deficits, diplopia, or blurring vision: Ocular migraine, brain mass lesion, or idiopathic intracranial hypertension Lacrimation and facial flushing: Cluster headache Rhinorrhea: Sinusitis Pulsatile tinnitus: Idiopathic intracranial hypertension Preceding aura: Migraine Focal neurologic deficit: Encephalitis, meningitis, intracerebral hemorrhage, subdural hematoma, tumor, or other mass lesion Seizures: Encephalitis, tumor, or other mass lesion Syncope at headache onset: Subarachnoid hemorrhage Myalgias and / or vision changes (in people> 50 years): Giant cell arteritis Past medical history should identify risk factors for headache, including use of medications or substances (particularly caffeine), withdrawal of caffeine, exposure to toxins (see table Disorders Causing Secondary Headache), recent lumbar puncture, use of immunosuppressants or IV drugs (risk of infection), hypertension (risk of brain hemorrhage), cancer (risk of brain metastases), dementia, trauma, coagulopathy, or use of anticoagulants or ethanol (risk of subdural hematoma).