Primary Headaches: Most common, not life-threatening. Examples include:

• Migraine: Throbbing pain, often unilateral, with nausea/vomiting, photophobia, or phonophobia.
• Tension-type: Dull, pressing pain, bilateral, no nausea/vomiting.
• Cluster: Severe, unilateral, orbital/supraorbital pain, with autonomic symptoms.

• Secondary Headaches: Require urgent evaluation if red flags present (e.g., sudden onset, fever, neurological deficits). Examples:
  • Subarachnoid hemorrhage: Sudden, severe "thunderclap" pain.
  • Meningitis: Severe pain, fever, neck stiffness.
  • Brain tumor: Progressive pain, focal neurological signs.

• Approach:
  • History: Onset, duration, triggers, associated symptoms.
  • Examination: Vital signs, neurological exam, signs of infection.
  • Investigations: CT/MRI if red flags present; otherwise, treat empirically.

Rationale: Primary headaches are benign and managed symptomatically. Secondary headaches require urgent workup due to potential serious causes.