What are the differential diagnoses and treatment options for a patient presenting with scalp pain and headache?

Differential Diagnoses for Scalp Pain and Headache

When a patient presents with scalp pain and headache, immediately assess for life-threatening secondary causes before considering primary headache disorders, with particular attention to cerebral venous thrombosis, giant cell arteritis in patients over 50, and spontaneous intracranial hypotension in those with orthostatic features.

Immediate Red Flag Assessment

Screen for the following features that mandate urgent evaluation:

• Focal neurologic deficits, altered consciousness, or confusion 1
• Sudden onset "thunderclap" headache (consider subarachnoid hemorrhage or cerebral venous thrombosis) 2, 1
• New headache in patients over age 50 (requires ESR and CRP to exclude giant cell arteritis) 2, 1
• Scalp tenderness, jaw claudication, or temporal pain in elderly patients (giant cell arteritis requires immediate temporal artery biopsy) 2
• Progressive worsening pattern or headache awakening patient from sleep 1
• Fever with headache (suggests meningitis) 1
• Papilledema or diplopia from sixth nerve palsy (suggests increased intracranial pressure) 2

Critical Secondary Causes with Scalp Involvement

Cerebral Venous Thrombosis (CVT)

CVT is a life-threatening condition that presents with headache in 90% of cases and can include scalp edema and dilated scalp veins on examination. 2

Clinical features include:

• Diffuse headache progressing over days to weeks (most common presentation) 2
• Scalp edema and dilated scalp veins (particularly with superior sagittal sinus thrombosis) 2
• Seizures occur in 40% of patients (distinguishing feature from other causes) 2
• Bilateral neurologic signs (paraparesis from sagittal sinus involvement) 2
• Isolated headache without focal findings occurs in 25% of cases (diagnostic challenge) 2

Diagnostic approach:

• Brain MRI with venography is the preferred imaging modality 2
• Median delay from symptom onset to diagnosis is 7 days (high index of suspicion required) 2

Giant Cell Arteritis (Temporal Arteritis)

In patients over 50 with scalp pain, jaw claudication, or temporal tenderness, immediately check ESR and C-reactive protein and perform temporal artery biopsy if elevated. 2

Key features:

• Scalp tenderness is a cardinal symptom 2
• Jaw claudication (pain with chewing) 2
• Risk of permanent vision loss if untreated 2

Spontaneous Intracranial Hypotension (SIH)

SIH presents with orthostatic headache that is absent or mild (1-3/10) on waking, develops within 2 hours of becoming upright, and improves >50% within 2 hours of lying flat. 2

Associated features:

• Scalp pain can occur as an associated symptom 2
• Neck pain is common 2
• Thunderclap presentation possible 2

Referral criteria:

• Refer to neurologist within 48 hours if patient cannot care for self but has help 2
• Emergency admission if patient cannot care for self and lacks help 2

Primary Headache Disorders with Scalp Pain

Nummular Headache

Nummular headache presents as continuous or intermittent pain confined to a round or oval area of scalp, typically 1-6 cm in diameter. 3

Management:

• Gabapentin is the most effective oral medication 3
• Subcutaneous onabotulinum toxin type A injection into the affected area is an effective alternative 3
• Exclude systemic and structural disease with physical examination, blood tests including immunology screening, and neuroimaging 3

Migraine with Scalp Allodynia

Migraine commonly causes scalp tenderness (allodynia) during attacks, with pain worsening with routine physical activity and associated with nausea or photophobia. 2, 4

Acute treatment algorithm:

• First-line: NSAIDs (aspirin, ibuprofen, naproxen sodium) or acetaminophen-aspirin-caffeine combination 2
• Second-line: Triptans (sumatriptan 50-100 mg provides headache response in 50-62% at 2 hours) 2, 5
• Alternative: CGRP antagonists (rimegepant or ubrogepant eliminate headache in 20% at 2 hours) 4
• Limit acute treatment to no more than 2 days per week to prevent medication-overuse headache 2, 6

Preventive therapy indications:

• ≥2 migraine attacks per month producing disability for ≥3 days 2
• Use of rescue medication more than twice per week 2
• First-line preventive: CGRP monoclonal antibodies (erenumab, fremanezumab, galcanezumab) reduce migraine days by 2-4.8 days/month 5

Cervicogenic Headache

Cervicogenic headache is provoked by cervical movement rather than posture, with associated neck pain and restricted cervical range of motion. 2, 5

Key distinguishing features:

• Pain provoked by cervical movement, not posture 2
• Reduced cervical range of motion 2
• Associated myofascial tenderness 2
• Medical imaging is not diagnostic (no difference in disc bulges between symptomatic and control patients) 5

Management:

• Exercise treatment is beneficial 5

Tension-Type Headache

Tension-type headache presents with bilateral pressing/tightening (non-pulsatile) pain of mild-to-moderate intensity without aggravation by routine activity. 5

This differs from migraine by:

• Bilateral rather than unilateral location 5
• Pressing rather than throbbing quality 5
• No worsening with routine activity 5

Idiopathic Stabbing Headache (Ice-Pick Headache)

Ice-pick headache presents as brief (seconds) stabbing pains in the scalp, which can occur in extratrigeminal locations including retroauricular, parietal, and occipital regions. 7

Management:

• Responds promptly to indomethacin 7
• Self-limited benign course 7

Diagnostic Algorithm

Step 1: Rule out red flags requiring emergency evaluation

• Perform focused neurologic examination for focal deficits, altered consciousness, papilledema, nuchal rigidity 1
• In patients >50 years: Check ESR and CRP immediately 2, 1
• If thunderclap onset or focal deficits: Non-contrast head CT emergently 5

Step 2: Characterize the headache pattern

• Orthostatic quality (worse upright, better lying flat): Consider SIH 2
• Scalp edema or dilated scalp veins: Consider CVT 2
• Localized round/oval area of scalp pain: Consider nummular headache 3
• Provoked by cervical movement: Consider cervicogenic headache 2
• Unilateral throbbing with nausea: Consider migraine 5, 4

Step 3: Obtain appropriate imaging based on clinical suspicion

• CVT suspected: Brain MRI with venography 2
• Giant cell arteritis suspected: Temporal artery biopsy after starting corticosteroids 2
• SIH suspected: Brain MRI with contrast (may show diffuse pachymeningeal enhancement) 2
• Typical primary headache without red flags: No imaging needed 1

Common Pitfalls to Avoid

• Do not assume primary headache disorder without excluding secondary causes, especially in patients over 50 1
• Do not miss CVT in patients with isolated headache (occurs in 25% of CVT cases without focal findings) 2
• Do not delay temporal artery biopsy in elderly patients with scalp tenderness (risk of permanent vision loss) 2
• Do not prescribe daily analgesics for chronic headache (leads to medication-overuse headache) 1
• Monitor for medication-overuse headache: triptans/ergots/combination analgesics ≥10 days/month for ≥3 months, or simple analgesics ≥15 days/month for ≥3 months 5
• Avoid triptans in patients with uncontrolled hypertension, cardiovascular disease, or basilar/hemiplegic migraine 2, 8