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Headache is a very common presenting complaint that can be encountered in most healthcare settings. However, there are a wide range of different types of headaches and while some are chronic and benign, some are worrying and require emergency care. It is important therefore to be able to spot the red flags to be able to determine the severity of a headache presentation.
In this article, the red flags of headaches will be explained, as well as describing some of the most common types of chronic headaches, their characteristics and the features that help differentiate them from each other.
To figure out red flags in headaches, let’s first explore the potential causes for acute headaches. What is important to establish with headaches is whether they are primary (i.e. idiopathic) or secondary (i.e. there is an underlying condition causing it).
Examples of secondary headaches that will prompt rapid investigation and emergency assessment are those due to a vascular condition (e.g. subarachnoid haemorrhage, sinus venous thrombosis, giant cell arteritis), infection or inflammation of the brain (e.g. meningitis, encephalitis, brain abscess), ophthalmic emergencies (e.g. acute glaucoma), or systemic hypertension, caused by pre-eclampsia for instance.
Many of these pathologies can increase intracranial pressure, which can manifest with specific signs such as papilloedema.
A vascular cause such as a subarachnoid haemorrhage presents with a thunderclap headache that is sudden in onset and very intense. These should narrow the diagnosis towards a vascular cause and should be treated as an emergency.
Accompanying systemic symptoms could indicate infection or systemic hypertension.
Neurologic symptoms can be indicative of the presence of a space-occupying lesion, while visual symptoms and eye pain may point towards acute glaucoma.
Any new-onset headache in patients over 50 years old should be treated as a secondary headache until proven otherwise, with particular concern for conditions such as giant cell arteritis or other intracranial pathology.
The following mnemonic can be used to memorise the main red flags: SPOON.
Table - The red flag symptoms of headaches, and which emergency condition each symptom might indicate
For more details on the investigation, diagnosis, and management of some of these secondary headaches, refer to the specific articles.
Brain tumours are a concern for many patients presenting with chronic headaches. It is important to ask specific questions to help rule this out before reassuring the patient, including signs of raised intracranial pressure, focal neurological signs (including more vague features such as personality change), and onset in patients over 50.
In adults, the most common brain tumours overall are secondary brain tumours, resulting from metastasis from other primary cancers. Tumours that commonly metastasise to the brain include lung, breast, colon, kidney and skin cancers.
Primary brain tumours arise in the brain or its associated structures. More than 12,000 people are diagnosed with a primary brain tumour each year in the UK, and about half of these tumours are cancerous (source).
Primary brain tumours may be non-cancerous or cancerous. Lower-grade tumours (grades 1 or 2) generally grow more slowly, while higher-grade tumours (grades 3 or 4) are generally more aggressive. Grade, tumour type and location all influence prognosis; a low-grade tumour can still cause serious problems.
There are many types of brain tumours, classified by their cellular and molecular features. Astrocytomas belong to the glioma group. The relative frequency of primary tumour types varies with age and the tumour categories included. Glioblastoma is an aggressive glioma; modern classification distinguishes IDH-wildtype glioblastoma from IDH-mutant astrocytoma. Other tumour types include vestibular schwannomas, which arise from Schwann cells, ependymomas, which arise from ependymal cells, and neuronal tumours.
Migraine usually presents as a unilateral, frontal headache that is often described as throbbing or pulsating. Episodes last from 4 to 72 hours. Migraine headaches are typically aggravated by light and noise, meaning patients may report phono- or photophobia, and prefer to be in a quiet, dark room. Most patients with chronic migraines find that going to sleep can help relieve symptoms, as well as taking medications such as triptans.
Some migraine episodes can be preceded by what is known as an ‘aura’, a characteristic feeling (can be visual, like flashing lights, sensory, like a strange smell or taste, etc.) and accompanied by nausea and vomiting in more severe cases. Some patients with chronic migraines find that their aura is so characteristic that they can predict when the headache is coming and can take medications to try to prevent the headache.
Pathophysiology of migraine is still unclear but there are factors that can trigger episodes such as certain foods (cheese, chocolate), stress, or lack of sleep. Family history also seems to play a role in susceptibility, and it affects women more than men. Most patients who suffer from migraines will have had their first episode before their 30s and the severity of the episodes seems to decrease with age.
Tension headache is the most common type of headache and typically presents as a bilateral frontal headache, sometimes radiating to the neck. It is often described as a squeezing, band-like type of pain and non-pulsatile with a mild to moderate intensity. It is usually worse at the end of the day as it is aggravated by stress, sleep deprivation, and poor posture.
It is considered chronic if it occurs on over 15 days per month for at least three months, or episodic if it happens less than that. It also affects women more than men and younger people. Onset after 50 years of age is unusual and should prompt assessment for secondary causes. In some cases, it can also present with mild nausea but usually responds to analgesics and rest. Pathophysiology is thought to be linked to tension building up in the occipitofrontalis muscle of the head and neck.
Medication overuse headache paradoxically arises from taking analgesia in the first place, most commonly as a treatment of headaches. It often presents with other co-morbidities such as depression and insomnia and can manifest with a variety of symptoms. It affects women more than men and typically within the 30-40 age range.
Medication overuse headache requires headache on at least 15 days per month in a patient with a pre-existing headache disorder, with regular medication overuse for more than 3 months and no better alternative diagnosis. For paracetamol and NSAIDs such as ibuprofen, overuse means use on at least 15 days per month. For opioids or triptans, the threshold is at least 10 days per month. These medication-use patterns must continue for more than 3 months. Count days of use, rather than the number of doses taken on each day.
Management includes withdrawal of the overused medication with appropriate clinical support and treatment of the underlying headache disorder. Headache may temporarily worsen during withdrawal, and improvement is not guaranteed within a fixed period. Opioid withdrawal requires a supervised plan.
Cluster headaches are an intense type of headache that is localised to the orbital area (patients usually complain of pain around or behind the eye) and described as sharp and penetrating. This is a type of headache that is more common in men than women and onset occurs between 20 and 40 years old. Onset of this type of headache is usually sudden and ‘attacks’ last from a few minutes up to a couple of hours and can occur several times a day for clusters of 2 to 12 weeks, with remissions of months to years between the clusters. Like tension headaches, they can be chronic or episodic.
They most commonly present at night and to be a diagnosed cluster headache there must also be signs of impaired sympathetic activity such as red, watery eyes, ptosis and nasal congestion. Episodes are also associated with a variety of triggers such as alcohol, histamine, GTN spray, heat, exercise, sleep deprivation and inhalation of solvents. Other factors thought to increase susceptibility are head trauma, alcohol consumption and smoking. Pathophysiology is still not well understood but high flow oxygen and specific acute therapies such as triptans have been shown to relieve symptoms; simple analgesics are usually ineffective.
Trigeminal neuralgia is a unilateral facial pain syndrome that occurs usually around the eye but can radiate to the lips, nose, and scalp, around the distribution of the trigeminal nerve (CN V). It is described as sharp and stabbing in nature almost like an ‘electric shock’ and it is severe in intensity.
Trigeminal neuralgia affects women more than men and has an increased incidence with age, usually peaking within the 50-60 age range.
Episodes occur with a rapid onset and last for a few seconds to minutes. Some triggers or factors that can make symptoms worse include eating, cold wind, vibration, or light touch to the face. Objective numbness or tingling is not typical of classical trigeminal neuralgia and, if present, should raise suspicion of a secondary cause rather than being considered an aura. It is caused by compression of the trigeminal nerve, most commonly by a vascular loop, although there can be other pathological causes such as tumours or multiple sclerosis. Symptoms are usually difficult to relieve, but antiepileptics can be useful in some patients.
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