What is the best course of treatment for a patient experiencing a unilateral headache localized behind the left eye and base of the skull?

Unilateral Headache Behind Left Eye and Base of Skull: Diagnostic and Treatment Approach

This presentation most likely represents either cluster headache or migraine, and the critical first step is distinguishing between these two conditions based on attack duration, frequency, and presence of ipsilateral autonomic symptoms.

Immediate Diagnostic Differentiation

Cluster headache should be suspected if:

• Attacks last 15-180 minutes (not days) 1, 2
• Pain is strictly unilateral, orbital, supraorbital, or temporal 3, 2
• Attacks occur 1-8 times per day during cluster periods 1
• Ipsilateral autonomic symptoms are present: conjunctival injection, lacrimation, nasal congestion, rhinorrhea, facial sweating, miosis, ptosis, or eyelid edema 3, 2
• Patient exhibits restlessness or agitation during attacks (cannot lie still) 2

Migraine should be suspected if:

• Attacks last 4-72 hours 3
• Pain is moderate to severe, often pulsating 3
• Accompanied by photophobia, phonophobia, nausea, or vomiting 3
• Pain is aggravated by routine physical activity 3
• May have visual or sensory aura symptoms lasting 5-60 minutes 3

Red Flags Requiring Immediate Neuroimaging

Obtain MRI (preferred) or CT immediately if any of the following are present: 1

• Sudden "thunderclap" onset 1
• Fever or unexplained systemic symptoms 3
• Headache worsened by Valsalva maneuver or exercise 1
• Abnormal neurologic examination 1
• Rapidly increasing frequency or severity 1
• New onset in patient over age 50 (consider temporal arteritis with parietal tenderness) 1

If parietal tenderness is present on examination, strongly consider temporal arteritis, particularly in patients over 50 years old 1

First-Line Abortive Treatment

If Cluster Headache is Diagnosed:

High-flow oxygen therapy is the gold-standard first-line treatment: 1

• Administer 12-15 liters per minute via non-rebreather mask 1
• Continue for 15-20 minutes 1
• Provides rapid relief within 15 minutes in 70-80% of patients 1

Alternative abortive option:

• Sumatriptan subcutaneous injection 6 mg is highly effective for cluster headache 4, 5

If Migraine is Diagnosed:

For mild to moderate attacks: 4

• NSAIDs as first-line: naproxen sodium 500-825 mg at onset (can repeat every 2-6 hours, maximum 1.5 g/day) 1, 4
• Alternative: combination aspirin + acetaminophen + caffeine 1, 4
• Ibuprofen, diclofenac potassium also effective 4

For moderate to severe attacks or inadequate response to NSAIDs: 4

• Add a triptan to the NSAID 4
• Oral sumatriptan 50-100 mg (doses of 100 mg may not provide greater effect than 50 mg but have greater risk of adverse reactions) 5
• Alternative triptans: rizatriptan, zolmitriptan, naratriptan 4
• Take triptans early when headache is still mild for maximum effectiveness 4
• Do NOT use triptans during aura phase 4

For attacks with nausea/vomiting:

• Use non-oral route: subcutaneous sumatriptan or DHE nasal spray 4
• Add antiemetic even if vomiting is not present 4

Dosing for sumatriptan tablets: 5

• Initial dose: 25 mg, 50 mg, or 100 mg 5
• If headache unresolved at 2 hours or returns, may give second dose at least 2 hours after first dose 5
• Maximum daily dose: 200 mg in 24 hours 5

Critical Medication-Overuse Prevention

Limit acute treatment to no more than 2 days per week to prevent medication-overuse headache (MOH) 1, 4

• MOH creates a vicious cycle of increasing headache frequency leading to daily headaches 1
• Regular overuse is defined as: non-opioid analgesics on ≥15 days/month for ≥3 months, or any other acute medication on ≥10 days/month for ≥3 months 3

When to Initiate Preventive Therapy

Consider preventive therapy if: 1

• Continuous headache of prolonged duration is present 1
• Attacks occur two or more times per month causing significant disability 1
• Patient is using acute medications more than 2 days per week 1

First-line preventive option for migraine:

• Propranolol 80-160 mg daily (long-acting formulation) 1

Follow-Up Strategy

Re-evaluate within 2-3 months to assess: 1

• Attack frequency and severity 1
• Migraine-related disability 1
• Adverse events from medications 1
• Adherence to treatment plan 1
• Use headache calendars to track symptomatic days and acute medication use 1

Common Pitfalls to Avoid

• Do not perform neuroimaging routinely without red flags - it is rarely necessary and can reveal clinically insignificant abnormalities that lead to unnecessary testing and patient anxiety 3
• Do not confuse cluster headache with migraine - the treatment approaches differ significantly, with oxygen being first-line for cluster headache 1
• Do not allow patients to overuse acute medications - this leads to medication-overuse headache and worsening of the primary condition 1
• Do not use triptans during the aura phase - wait until headache begins 4
• If one triptan fails, try another - individual response varies 4