Red flag symptoms: Headaches

Differentiate causes of primary and secondary headaches.

  • Onset of headaches >50 years
  • Thunderclap headache - subarachnoid haemorrhage
  • Neurological symptoms or signs
  • Meningism
  • Immunosuppression or malignancy
  • Red eye and haloes around lights - acute angle closure glaucoma
  • Worsening symptoms
  • Symptoms of temporal arteritis

Headache is a common neurological presentation in primary care and may be primary or secondary.

Primary headache includes tension-type headaches, cluster headaches and migraine. Secondary headache may be caused by glaucoma, sinusitis, intracranial malignancy, haemorrhage, idiopathic intracranial hypertension and infection.1

Headaches may cause significant morbidity and can result in absence from work or school. The most common types are tension-type headaches and migraines.

Red flag symptoms should be excluded to rule out more serious causes of headache. It is of note that intracranial masses do not usually cause headache.1

Clinical assessment

History taking involves assessing the location of the headache, its onset, severity, duration, and exacerbating and relieving factors.

Possible triggers may include coughing, sneezing, exercising, changes in posture and onset of menses. It is helpful to assess whether there have been previous episodes and if so, whether there has been a change in the pattern or severity of the headache.

The nature of the pain, as well as how debilitating the headache is, should be assessed. It is useful to find out what treatments have been tried and any response to them.

New headaches presenting in a patient over the age of 50 years may indicate temporal arteritis.1

Other relevant features may include nausea and vomiting, fever, and visual symptoms including red eye, visual field defects, blurring and diplopia. The presence of lacrimation and facial flushing may be suggestive of cluster headaches.1

Carbon monoxide poisoning may present with headaches, vomiting, muscle weakness and diplopia.1 There may be a history of an aura in migraine and pulsatile tinnitus may be suggestive of idiopathic intracranial hypertension. If clinically appropriate, asking the patient to keep a headache diary may be helpful.

Focal neurology may indicate intracerebral pathology, a bleed or infection. Neurological signs may include impaired level of consciousness, weakness, new onset seizures or papilloedema. Headache associated with vomiting, drowsiness or changes in posture may be caused by raised intracranial pressure.1

A thunderclap headache refers to a severe headache of sudden onset - this may indicate subarachnoid haemorrhage. It is helpful to exclude head trauma occurring within the past three months of the headache.1

Red eye and haloes around lights may indicate acute angle closure glaucoma. Risk factors include a family history and hypermetropia.1

A rare cause of headache, found more commonly in young obese women, is idiopathic intracranial hypertension.1 The history may suggest features of raised intracranial pressure and papilloedema may be found on clinical examination.

Physical examination should include vital signs and a full neurological examination. Eye examination should include pupillary reflexes, extraocular movements, fundoscopy and visual field assessment. It may be necessary to exclude meningism.

If temporal arteritis is suspected, the scalp should be examined for swelling and tenderness, and there may be a history of jaw claudication.

Causes of secondary headache

  • Intracranial malignancy
  • Haemorrhage
  • Idiopathic intracranial hypertension
  • Infection - encephalitis, meningitis
  • Giant cell artteritis
  • Analgesic overuse
  • Carbon monoxide poisoning


Depending on the clinical cause, it may be appropriate to arrange blood tests. The presentation may warrant immediate referral to hospital, for example, in suspected subarachnoid haemorrhage.

In cases of suspected temporal arteritis, immediate management with high-dose steroids is required to prevent blindness.

If a patient presents with recent headaches associated with signs of raised intracranial pressure, urgent referral should be made via the two-week wait pathway.2

If a patient presents with headaches associated with focal or non-focal neurology, urgent referral should be made, if appropriate.2

Non-focal neurology may refer to cognitive changes and altered mental status. Urgent referral is recommended by NICE if there is a change in the usual pattern of headache, with increasing severity.2

If there is a history of malignancy in a patient with new onset seizures, neurological deficit or signs, persistent headaches and/or altered mental status or cognitive changes, urgent referral is recommended.2

A history of new onset headache in patients who are immunocompromised, for example, in relation to HIV or immunosuppressive therapy, a history of malignancy known to cause cerebral metastases and vomiting in the absence of other causes may warrant referral for further investigation.2

  • Dr Kochhar is a GP in Bexhill, East Sussex

Click here to take a test on this article and claim a certificate on MIMS Learning

This is an updated version of an article that was first published in August 2015.

Picture: iStock


1. NICE. Headaches: Diagnosis and management of headaches in young people and adults. CG150. London, NICE, September 2012.

2. NICE. Referral guidelines for suspected cancer. CG27. Quick Reference Guide. London, NICE, June

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