Differential Diagnosis

Common Diagnoses

Occasional Diagnoses

Rare Diagnoses

  • Cluster Headache
  • Intracranial Lesion (e.g. Carcinoma, Abscess, Haematoma, Benign Intracranial Hypertension)
  • Meningitis
  • Intracerebral Haemorrhage
  • Carbon Monoxide Poisoning (Blocked Boiler Flue)
  • Paget’s Disease of Skull
  • Severe Hypertension
  • Pre-Eclampsia

Ready Reckoner

Key distinguishing features of the most common diagnoses

Tension Frontal SinusitisMigraineCervical SpondylosisEye Strain
Worse on Lying DownNoYesNoPossibleNo
Congested NoseNoYesPossibleNoNo
Worse on Neck MovementNoNoPossibleYesNo
Tender at Point of PainPossibleYesNoNoNo

Possible Investigations


Possible:FBC, ESR/CRP.

Small Print:U&E, alkaline phosphatase, x-ray of sinuses, cervical spine or skull, CT scan, sleep studies, lumbar puncture.

  • FBC: WCC raised in abscess and sinusitis. ESR/CRP essential if arteritis suspected.
  • U&E: Na+/K+ derangement in pituitary tumours, alkaline phosphatase raised in Paget’s disease.
  • X-ray: May see fluid levels in sinusitis (rarely useful in diagnosis). May confirm cervical spondylosis and Paget’s disease.
  • CT scan: To exclude intracranial lesion.
  • Sleep studies: If sleep apnoea suspected.
  • Lumbar puncture: In suspected meningitis; may also help in diagnosis of benign intracranial hypertension.

Top Tips

  • Explore the patient’s fears: The majority are worried about serious pathology, such as a brain tumour, and may leave the consultation dissatisfied unless this specific worry is addressed.
  • Another common concern is hypertension. Patients will expect to have their blood pressure checked, even though this is almost never the cause of the symptom.
  • Analgesics may paradoxically exacerbate tension headache. It is more constructive to adopt alternative approaches, such as relaxation techniques or antidepressants, as appropriate.
  • Headache caused by an intracranial lesion usually produces other neurological symptoms or signs.

Red Flags

  • Suspect subarachnoid haemorrhage given a history of sudden explosive headache. It is frequently described as ‘like a blow to the head’.
  • If temporal arteritis is suspected, treat immediately. The ESR provides retrospective confirmation only.
  • Beware of the pregnant woman complaining of headache in the third trimester – check the blood pressure, ankles and urinalysis. Headache, particularly with visual disturbance, may be a symptom of impending eclampsia.
  • A new and increasing headache present on waking and increased by stooping or straining may be due to raised intracranial pressure. Check for other symptoms and signs and refer urgently if in doubt.
  • If a headache feels and smells like migraine, then it’s a migraine regardless of age. However, beware of making this the diagnosis in the elderly without systematically ruling out more sinister causes first.

Published: 2nd August 2022 Updated: 10th April 2024

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