Workup for Chronic Daily Headache
The workup for chronic daily headache is primarily clinical, based on a comprehensive headache history and physical examination to identify red flags requiring neuroimaging, with most patients not requiring routine laboratory tests or imaging when the history and exam are consistent with primary headache disorders. 1
Initial Clinical Assessment
Essential History Components
The medical history is the cornerstone of diagnosis and must systematically capture: 1
- Age at headache onset (migraine typically begins at or around puberty)
- Headache frequency (≥15 days/month defines chronic daily headache) 2, 3
- Duration of individual episodes (4-72 hours for migraine; variable for tension-type)
- Pain characteristics: location (unilateral vs bilateral), quality (pulsating vs pressing), severity, aggravating factors (routine physical activity)
- Associated symptoms: photophobia, phonophobia, nausea, vomiting 1
- Aura symptoms if present (visual, sensory, speech/language disturbances that spread gradually over ≥5 minutes) 1
- Medication use history: critical to identify medication overuse (≥10 days/month for triptans/combination analgesics or ≥15 days/month for simple analgesics for >3 months) 1
- Family history of migraine (strengthens diagnostic suspicion) 1
Diagnostic Tools
Implement headache diaries prospectively to record daily headache occurrence, characteristics, associated symptoms, and medication use—these serve as both diagnostic aids and tools for ongoing assessment. 1 Headache calendars can track temporal patterns including menstrual relationships. 1
Screening questionnaires like the ID-Migraine (3 questions on nausea, photophobia, disability) can help identify migraine likelihood. 1
Red Flags Requiring Neuroimaging
Perform MRI of the head when any of the following red flags are present: 3, 4
- Sudden onset or "thunderclap" pattern
- New headache in patients >50 years old
- Progressive worsening despite treatment
- Focal neurological signs or symptoms
- Papilledema or signs of increased intracranial pressure
- Headache triggered by Valsalva, exertion, or position change
- Systemic symptoms (fever, weight loss)
- History of cancer, HIV, or immunosuppression
- New headache in pregnancy or postpartum
Classification After Excluding Secondary Causes
Once secondary headaches are ruled out clinically or through investigation, classify by attack duration: 4
If attacks last <4 hours:
Consider trigeminal autonomic cephalalgias (cluster headache, paroxysmal hemicrania, SUNCT, hypnic headache) 4
If attacks last ≥4 hours:
Classify as primary chronic daily headache: 2, 5, 6
- Chronic migraine: ≥15 headache days/month for >3 months, with ≥8 days/month meeting migraine criteria 1
- Chronic tension-type headache: bilateral, pressing/tightening quality, mild-moderate intensity, not aggravated by routine activity
- New daily persistent headache: abrupt onset over <3 days, becoming continuous
- Hemicrania continua: continuous unilateral headache, absolutely responsive to indomethacin 5, 6
Critical Comorbidity Assessment
Identify medication overuse headache, which occurs in patients with pre-existing headache disorder who overuse acute medications (≥10 days/month for triptans/opioids/combination analgesics or ≥15 days/month for simple analgesics for >3 months). 1 This must be recognized and addressed as it perpetuates the chronic headache pattern.
Screen for psychiatric comorbidities including depression, bipolar disorder, generalized anxiety disorder, and obsessive-compulsive disorder, as these are highly comorbid with chronic migraine and must be treated concurrently for successful headache management. 5
Laboratory and Additional Testing
Routine laboratory tests are not indicated in the absence of clinical suspicion for secondary causes. 3 Blood work should be directed by specific clinical concerns (e.g., ESR for temporal arteritis in older patients, thyroid function if clinically indicated).
Lumbar puncture is reserved for suspected secondary causes such as idiopathic intracranial hypertension, meningitis, or subarachnoid hemorrhage when imaging is unrevealing but clinical suspicion remains high. 1
Common Pitfalls
The most critical error is failing to identify medication overuse, which affects treatment response and must be addressed before preventive therapy can be optimally effective. 1, 2 Another pitfall is over-reliance on imaging when the history and examination are consistent with primary headache—this leads to unnecessary costs and potential false-positive findings. 3, 4
Specialist referral is indicated for patients with chronic migraine, particularly when complicated by medication overuse or when initial management fails. 1