Red flag symptoms: Headache

Most headaches are benign primary headaches with no serious underlying cause.

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  • Sudden onset
  • Age of onset > 50 years
  • Increased frequency or severity
  • Previous head trauma
  • Underlying medical conditions
  • Loss of consciousness
  • Meningism
  • Sepsis
  • Vomiting

However, in a minority of patients this ubiquitous symptom may herald a more sinister aetiology.

The red flag symptoms above should alert the clinician to act promptly.

The British Association for the Study of Headache (BASH) has produced guidelines on the diagnosis of various types of headaches. History taking is essential for diagnosing the type of headache.

Consider the age of the patient when making a diagnosis of migraine.

Migraines usually present in younger patients. Migraines are typically recurrent episodic headaches lasting up to three days. They may be accompanied by GI symptoms and photophobia. The characteristic aura is not always present and should not be confused with visual disturbances.

When a headache has a serious underlying cause, a patient will often present with additional symptoms. In the absence of other symptoms, a sudden onset headache or a recent change in the type of headache should be cause for concern. In addition to worsening headaches, intracranial tumours may cause nausea and vomiting, seizures and neurological disturbance. Abnormal neurological findings on clinical examination warrant referral for further investigation.

Sinister causes
Consider intracranial lesions, particularly in patients with a history of malignancy or immunodeficiency.

Meningitis should be considered in the generally unwell patient presenting with a progressive headache. The headache is usually generalised or frontal and worsens over a period of hours, sometimes accompanied by a stiff neck or nausea. Immediate referral is warranted in this case. A lumbar puncture will confirm or rule out meningitis.

Subarachnoid haemorrhage often, but not always, presents with a sudden-onset headache, described by the patient as the worst pain they have ever felt. This may be accompanied by nausea and a stiff neck. It may be difficult to distinguish from meningitis.

A severe, persistent headache in a patient over 50 may be suggestive of giant cell arteritis. The patient is likely to be unwell, and to present with jaw claudication and scalp tenderness. The temporal arteries are tender and pulseless.

Be aware of medication overuse headache as a diagnosis. Medication overuse headache results most commonly from patients taking medications intended to treat headache. Opiates, aspirin, NSAIDs and paracetamol are all associated with this condition.

Possible causes

  • Migraine
  • Tension-type headache
  • Head trauma
  • Systemic infection
  • Venous thrombosis
  • Hypoglycaemia
  • Meningitis
  • Benign intracranial hypertension
  • Malignancy
  • Subarachnoid haemorrhage
  • Sinusitis
  • Eye strain


BASH guidelines, 2007.

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