Headaches can be classified as either primary or secondary in nature. The most common primary headache syndrome is migraine. True tension headache and cluster headaches are uncommon. The diagnosis in these cases is made entirely from the history because there are no physical signs. Headache can also be secondary to other disorders affecting the head and neck, and it is sometimes the predominant symptom of serious intracranial disease such as a brain tumour, infections of the brain parenchyma or meninges or a subarachnoid haemorrhage. The most common cause of secondary headache is systemic infection.
The approach to assessing a patient with headache should be based on the temporal pattern of symptoms, especially the mode of onset and subsequent course. This may be:
- recurrent and episodic with acute or subacute onset
- chronic and daily with fluctuations in severity over months or years
- new daily persistent headache
- subacute onset and progressive over days to weeks
- acute onset and progressive over hours
Common causes of recurrent episodic headache
- Unilateral subacute onset throbbing headache exacerbated by movement and typically lasting 4 to 72 hours
- Accompanied by nausea, vomiting, vertigo, photo-, phono- and osmophobia±aura symptoms (visual, sensory, motor, or speech)
- May be triggered by bright light, strong smells, loud sounds, sleep deprivation/excess, exercise, tiredness, hunger/dehydration, fatigue, exercise, menstruation
- Severe unilateral retro/periorbital±temporal pain of acute onset reaching crescendo within minutes
- Associated autonomic features: conjunctival injection/lacrimation, ptosis, miosis, nasal congestion/rhinorrhoea, facial flushing/ sweating/pallor
- Associated restlessness/agitation
- Attacks last 15–180 minutes, can occur up to 8 times per day and may have circadian periodicity
- Triggered by alcohol
Tight band around the head or a pressure-like sensation; usually mild to moderate severity and waxes and wanes lasting variable amount of time; otherwise completely featureless.
Chronic daily headache
Chronic daily headache is a descriptive term that is characterized by headaches occurring >15 days per month. The most common cause is chronic migraine, which is complicated by medication overuse headache. Medication overuse headache is the term used when a primary headache develops or worsens when painkillers are taken too frequently (>8 to 10 days per month), and is typically preceded by an episodic headache disorder.