Emergency red flags — go to hospital immediately if headache is:
- Sudden onset — worst headache of your life (thunderclap headache)
- Associated with neck stiffness, fever, or rash (possible meningitis)
- Following a head injury
- With new neurological symptoms: vision loss, weakness, speech difficulty
- Waking you from sleep progressively worsening over days-weeks
Blood tests ordered for headache
| Test | What it checks for |
|---|---|
| ESR | Very high ESR >50 in elderly — suggests giant cell arteritis (temporal arteritis) |
| CRP | Active inflammation — infection, vasculitis, autoimmune |
| CBC | Infection (high WBC), anaemia (low Hb can cause headache) |
| Glucose | Hypoglycaemia and very high blood sugar both cause headache |
| TSH | Hypothyroidism and hyperthyroidism cause headaches |
| Sodium | Low sodium (hyponatraemia) causes severe headache and confusion |
| Blood pressure check | Hypertensive headache — BP >180/120 |
| Lumbar puncture (CSF) | If subarachnoid haemorrhage or meningitis suspected |
Common headache types and their features
Tension headache (most common — 70% of headaches)
Bilateral pressing or tightening sensation, mild to moderate severity, not worsened by activity. Not pulsating. No nausea. Often related to stress, poor posture, eye strain or dehydration. Blood tests normal. Treatment: paracetamol, ibuprofen, rest, hydration.
Migraine
Moderate-to-severe pulsating pain, usually one-sided, lasting 4-72 hours. Often accompanied by nausea, vomiting, sensitivity to light (photophobia) and sound (phonophobia). May have aura (visual zig-zag lines, blind spot, tingling) before headache. Triggered by stress, hormones, certain foods (red wine, cheese, chocolate), sleep changes. Blood tests normal. Requires specific migraine treatment (triptans).
Cluster headache
Excruciating, strictly one-sided pain around one eye, with watering eye and blocked nostril on same side. Occurs in clusters over weeks, then remits for months. Predominantly affects men. Blood tests normal. Treated with high-flow oxygen and sumatriptan injection.
Giant cell arteritis (temporal arteritis)
Occurs almost exclusively in people over 50. Severe temporal (side of head) pain, jaw claudication (pain when chewing), scalp tenderness, and risk of sudden vision loss. ESR is typically extremely high (>50, often >100 mm/hr). CRP also elevated. Treated urgently with high-dose prednisolone to prevent blindness. Temporal artery biopsy confirms diagnosis.
Medication overuse headache (rebound headache)
Paradoxically, taking too many painkillers (>10-15 days per month) for headache causes chronic daily headache. All painkillers worsen it. Treatment: gradual painkiller withdrawal, preventive medication.
Blood pressure and headache
Hypertension alone rarely causes headache except at very high levels (>180/120 mmHg — hypertensive crisis). Most patients with chronic hypertension do not have headache. However, a hypertensive crisis with headache, confusion or visual changes is a medical emergency.
Questions to ask your doctor
- Is my headache pattern concerning for a serious cause?
- Should I have an ESR to rule out giant cell arteritis?
- Do I need a brain CT or MRI?
- Is medication overuse contributing to my headaches?
- Should I see a neurologist?