How should I classify and manage unilateral left‑sided facial and eye pain in an adult without a clear two‑day onset?

Classification and Management of Unilateral Left-Sided Facial and Eye Pain Without Clear Two-Day Onset

This presentation most likely represents migraine with atypical facial localization, and you should initiate a trial of triptans for acute episodes while evaluating for red flags that would indicate alternative diagnoses. 1, 2

Immediate Red Flag Assessment

Before classifying this as migraine, you must urgently exclude giant cell arteritis if the patient is over 50 years old by checking ESR and C-reactive protein within hours, as this is a vision-threatening emergency that can cause irreversible blindness if missed. 1, 3 Look specifically for:

• Jaw claudication during chewing 1, 3
• Temporal artery tenderness or absent pulse 3
• Visual disturbances or changes 3
• Scalp tenderness 3
• Constitutional symptoms (fever, malaise, weight loss) 3

Diagnostic Classification Framework

Most Likely Diagnosis: Migraine with Isolated Facial Pain

The absence of a clear "two-day onset" should not exclude migraine from your differential. The International Headache Society criteria require attacks lasting 4-72 hours (not specifically two days), and migraine can present with isolated facial pain in the V2 and V3 trigeminal distributions without typical temporal or frontal headache. 1, 2

Classify this as migraine if at least two of these features are present:

• Unilateral location (which this patient has) 4
• Throbbing or pulsatile character 4, 1
• Moderate to severe intensity 4, 1
• Worsening with routine physical activity 4, 1

Plus at least one of:

• Nausea and/or vomiting 4, 1
• Photophobia and phonophobia 4, 1

Critical Diagnostic Pitfall

The American Academy of Neurology reports that 68-95% of patients self-diagnosed with "sinus headache" actually have migraine or tension-type headache. 1 Do not diagnose sinusitis based on facial pain alone without purulent nasal discharge, and avoid prescribing antibiotics for symptoms less than 10 days unless severe or worsening. 1

Alternative Diagnoses to Consider

Trigeminal neuralgia presents as severe electric shock-like pain provoked by light touch, typically episodic rather than continuous, and responds best to carbamazepine. 4, 1 This is less likely if the pain is continuous or lacks trigger points.

Temporomandibular disorder (TMD) causes dull, aching pain in jaw muscles worsened by chewing, jaw movement, or clenching, and is the most common non-dental cause of chronic facial pain with 5-12% prevalence. 3 However, TMD typically lacks the throbbing quality and associated migraine features.

Cluster headache requires five attacks with severe unilateral orbital, supraorbital, or temporal pain lasting 15-180 minutes with ipsilateral autonomic features (lacrimation, nasal congestion, ptosis, miosis, eyelid edema). 4 The absence of these autonomic features makes cluster headache unlikely.

Diagnostic Workup

History Elements to Elicit

Document the exact duration of each episode (not just "no sure 2 day onset"), as migraine requires 4-72 hour duration per attack. 1, 5 Specifically ask about:

• Timing: exact onset, duration of each episode, and frequency per month 4
• Quality: throbbing vs. stabbing vs. burning vs. aching 4
• Triggers: hormonal changes, certain foods, sensory stimuli (light, smells), missed meals, stress relief 4
• Aggravating factors: routine activity, chewing, touching the face 4, 1
• Associated symptoms: nausea, vomiting, light sensitivity, sound sensitivity, visual distortions, nasal symptoms, eye tearing 4

Physical Examination

Perform a thorough neurologic examination looking for any focal deficits that would necessitate neuroimaging. 4 Examine:

• Temporal arteries for tenderness or absent pulse (if age >50) 3
• Oral cavity and dentition for dental pathology 3
• Temporomandibular joints for tenderness, clicking, or limited range of motion 3
• Facial sensation in all three trigeminal distributions 4
• Trigger points for trigeminal neuralgia 4

Neuroimaging Indications

The U.S. Headache Consortium guidelines do not recommend neuroimaging if the patient has typical migraine features without atypical patterns or neurologic signs. 4 However, order MRI of the brain and trigeminal nerve if you find:

• Atypical headache patterns 4
• Any neurologic signs on examination 4
• Progressive pain 3
• Sensory disturbances 3
• Need to exclude tumors, multiple sclerosis, or neurovascular compression 3

Management Algorithm

Acute Treatment

Initiate a trial of triptans for acute episodes, as migraine with isolated facial pain responds well to triptan therapy. 2 This diagnostic-therapeutic trial can help confirm the diagnosis if the patient responds favorably.

For acute migraine treatment, the American Academy of Neurology recommends triptans as first-line therapy. 1

Preventive Treatment Considerations

Consider preventive therapy if:

• Headaches occur on ≥8 days per month (chronic migraine definition) 1, 5
• Acute treatments are ineffective or contraindicated 5
• Patient experiences significant disability 5

For episodic migraine prevention, options include topiramate or amitriptyline. 1 Beta-blockers and valproic acid have also shown efficacy in patients with facial migraine presentations. 2

For chronic migraine (≥15 days/month for ≥3 months with migraine features on ≥8 days/month), onabotulinumtoxinA injections are the only FDA-approved preventive treatment. 5

If Triptan Trial Fails

If the patient does not respond to triptans after adequate trials, reconsider the diagnosis:

• For trigeminal neuralgia: Start carbamazepine as first-line treatment, and consider neurosurgery referral if poorly controlled. 4, 1
• For TMD: Provide patient education, jaw rest, heat or cold therapy, NSAIDs, and supervised jaw exercises and stretching. 3 Consider night splints fabricated by a dentist. 6
• For neuropathic pain: Use gabapentin 300mg at bedtime, titrating to 900-3600mg daily in divided doses, or amitriptyline. 6

Referral Indications

Refer to a specialized neurologist for headache and facial pain if:

• Diagnosis remains unclear after initial evaluation 1
• Patient fails to respond to appropriate acute and preventive treatments 6
• Red flags are present requiring subspecialty evaluation 1, 3
• Giant cell arteritis is suspected (immediate referral) 3
• Malignancy is suspected (referral within 1-2 weeks) 3

Key Clinical Pearls

The heterogeneous clinical presentation of migraine can be difficult to diagnose even for headache specialists, and migraine can present with pain localized exclusively to the face in V2 and V3 distributions without typical temporal headache. 2 The lack of a specific "two-day" onset should not exclude migraine, as the diagnostic criteria specify 4-72 hours per attack, not exactly two days. 1, 5

Do not miss giant cell arteritis in patients over 50 years old, as this represents a medical emergency requiring immediate corticosteroid therapy to prevent permanent vision loss. 1, 3