Assessing new-onset headache

A new-onset headache may result from a primary headache syndrome or be secondary to other pathology. When assessing the patient, first consider whether they have any 'red flags' that suggest they need urgent evaluation (eg neuroimaging, lumbar puncture, urgent expert/emergency department review; see Warning features in a patient with new-onset headache).

Table 1. Warning features in a patient with new-onset headache
Symptoms and signs associated with new-onset headache that suggest urgent evaluation is needed	Possible diagnosis
sudden onset	subarachnoid haemorrhage, pituitary apoplexy, haemorrhage into mass lesion, arterial dissection, reversible cerebral vasoconstriction syndrome
first ever headache with focal neurological signs, confusion or drowsiness	stroke, venous sinus thrombosis, reversible cerebral vasoconstriction syndrome, meningitis/encephalitis
patient older than 50 years	giant cell arteritis, mass lesion, stroke
onset after head trauma	subdural/epidural haemorrhage
frequency/severity increases over weeks to months	mass lesion, subdural haemorrhage, analgesic rebound
new onset in patient who has HIV or cancer, or is immunosuppressed	meningitis, abscess, metastasis
signs of systemic illness (eg fever, rash, neck flexion stiffness)	systemic infection, meningitis, encephalitis, vasculitis
papilloedema	mass lesion, idiopathic intracranial hypertension, venous sinus thrombosis
positional headache (eg worse when lying down) and cough headache (especially if prolonged)	space-occupying or posterior fossa lesion, Chiari malformation