What is the most likely diagnosis for a patient with severe, unilateral orbital pain, short-duration attacks, and associated autonomic symptoms such as tearing and nasal congestion on the same side as the headache?

Cluster Headache

This patient has cluster headache, characterized by the severe unilateral periorbital pain lasting 90 minutes, multiple daily attacks, ipsilateral autonomic symptoms (tearing and nasal congestion), restlessness during attacks (pacing), and seasonal clustering pattern. 1

Diagnostic Features That Confirm Cluster Headache

The presentation meets the International Headache Society diagnostic criteria requiring:

• Severe unilateral pain in the orbital/periorbital region lasting 15-180 minutes (this patient has 90-minute attacks) 1, 2
• Frequency of 1-8 attacks daily (this patient has "a few times a day") 1, 3
• Ipsilateral autonomic symptoms including lacrimation and nasal congestion on the right side only 1, 2
• Restlessness or agitation during attacks (the patient paces and cannot lie down) 2, 3
• Clustering pattern with attacks occurring in bouts during specific times of year (symptoms recurred "this time last year") 2, 4

Why Other Diagnoses Are Excluded

Migraine without aura is ruled out because:

• Migraine attacks last 4-72 hours, not 90 minutes 5, 1
• Migraine patients prefer to lie still in a dark, quiet room, whereas this patient paces and finds lying down unhelpful 1
• Migraine typically has photophobia, phonophobia, and nausea/vomiting rather than prominent autonomic features 5

Giant cell arteritis is excluded because:

• This affects patients over age 50 (this patient is 35 years old) 5
• It presents with continuous dull aching pain, jaw claudication, and systemic symptoms like fever and malaise 5
• The short-duration paroxysmal attacks with complete resolution between episodes are incompatible with arteritis 5

Carotid artery dissection is ruled out because:

• Dissection causes continuous pain, not episodic 90-minute attacks 6
• It would present with focal neurological deficits and requires urgent vascular imaging 6

Medication-overuse headache is excluded because:

• This requires ≥15 headache days per month with regular overuse of acute medications for >3 months 5
• The patient has no history of chronic medication use mentioned 5
• The episodic clustering pattern with remission periods is incompatible with medication-overuse headache 5

Clinical Pearls and Common Pitfalls

Key distinguishing feature: The combination of short-duration attacks (15-180 minutes), restlessness during pain, and strict unilateral autonomic symptoms is pathognomonic for cluster headache and distinguishes it from all other headache disorders 1, 3

Circadian and circannual rhythmicity is characteristic—attacks often occur at the same time each day (especially at night) and during the same months each year 2, 7

Male predominance: Cluster headache is 2-3 times more common in males, with mean onset at age 30 4

Common triggers during bouts include alcohol, strong odors (solvents, cigarette smoke), and napping 2, 4

Diagnostic delay is common: Many patients experience misdiagnosis, which delays appropriate treatment 3