What causes headaches?

Causes of Headaches

Headaches are primarily caused by primary disorders like migraine and tension-type headaches, with secondary causes being much less common but potentially more serious.

Primary Headache Disorders

Migraine

• Affects approximately 55% of children with headaches and has a lifetime prevalence of 22.3% in adult women and 10.8% in adult men 1, 2
• Characterized by:
  • Moderate to severe throbbing pain, often unilateral
  • Exacerbation by physical activity
  • Associated symptoms including photophobia, phonophobia, nausea, and vomiting 2
• Pathophysiology involves disruption of normal neural networks of the head, leading to meningeal vasodilation and inflammation 2
• Often misdiagnosed as "sinus headache" - approximately 68% of patients with self-described or physician-labeled "sinus headache" actually meet criteria for migraine 3
• Cranial autonomic symptoms (like rhinorrhea) occur in approximately 62% of pediatric migraineurs, contributing to misdiagnosis as sinus-related 1

Tension-Type Headache

• Accounts for approximately 30% of headaches in children 1
• Characterized by:
  • Bilateral, mild to moderate pain
  • Pressing or tightening quality
  • Not aggravated by routine physical activity
  • Lacks the accompanying symptoms typical of migraine 1
• Represents about 27% of headaches misdiagnosed as "sinus headaches" 3

Secondary Headache Disorders

Medication Overuse Headache

• Important differential diagnosis for chronic headache 1
• Develops from overuse of acute headache medications, including over-the-counter analgesics 4
• Frequent use of medications like ergotamine, opiates, analgesics, and triptans may cause medication-overuse headaches 1
• Can transform episodic headaches into chronic, intractable headaches through central sensitization 4

Sinusitis-Related Headache

• True sinus headaches are uncommon, accounting for only about 5% of headaches initially diagnosed as "sinus headaches" 3, 5
• Genuine sinusitis-related headache typically occurs only with:
  • Acute bacterial infection where sinus drainage is blocked
  • Usually unilateral pain due to trapped pus causing increased pressure and inflammation
  • Associated with fever and unilateral nasal obstruction 5
• Chronic sinusitis is not validated as a cause of headache unless relapsing into an acute stage 5

Brain Tumors

• Rarely cause headache as an isolated symptom 1
• In children with brain tumors:
  • 94% have abnormal neurologic findings at diagnosis
  • 60% have papilledema
  • Other findings include gait disturbance, abnormal reflexes, cranial nerve findings, and altered sensation 1
• Less than 1% of children with headache who undergo MRI have relevant findings to explain the headache (such as tumor with hydrocephalus) 1
• "Classic" brain tumor headache (worse in morning/lying down, aggravated by Valsalva maneuvers, accompanied by nausea/vomiting) is uncommon at initial presentation 6

Red Flags Suggesting Secondary Headache

• Headache that worsens with Valsalva's maneuver
• Headache that awakens the patient from sleep
• Newly onset headache in an older person
• Progressively worsening headache
• Thunderclap headache
• Atypical aura
• History of head trauma
• Unexplained fever
• Impaired memory
• Focal neurological symptoms 1

Other Causes

• Vascular disorders (cranial or cervical)
• Nonvascular intracranial disorders
• Substance use or withdrawal
• Infections
• Disorders of homeostasis
• Psychiatric disorders
• Disorders of the cranium, neck, eyes, ears, nose, sinuses, teeth, mouth, or other facial structures 1

Understanding the correct cause of headache is crucial for proper treatment and to avoid unnecessary interventions such as inappropriate antibiotic use, imaging, or surgical procedures 3.