Headache is pain in any part of the head, including the scalp, face (including the orbitotemporal area), and interior of the head. Headache is one of the most common reasons patients seek medical attention.

Pathophysiology

Headache is due to activation of pain-sensitive structures in or around the brain, skull, face, sinuses, or teeth.

Etiology

Headache may occur as a primary disorder or be secondary to another disorder. Primary headache disorders include migraine, cluster headache (including chronic paroxysmal hemicrania and hemicrania continua), and tension-type headache. Secondary headache has numerous causes (see Table 1: Headache: Disorders Causing Secondary Headache).

Overall, the most common causes of headache are

Tension-type headache

Migraine

Some causes of headache are common; others are important to recognize because they are dangerous, require specific treatment, or both (see Table 2: Headache: Some Characteristics of Headache Disorders by Cause).

Table 1

Disorders Causing Secondary Headache

Cause
Examples

Extracranial disorders
Carotid or vertebral artery dissection (which also causes neck pain)

Dental disorders (eg, infection, temporomandibular joint dysfunction)

Glaucoma

Sinusitis

Intracranial disorders
Brain tumors and other masses

Chiari type I malformation

CSF leak with low-pressure headache

Hemorrhage (intracerebral, subdural, subarachnoid)

Idiopathic intracranial hypertension

Infections (eg, abscess, encephalitis, meningitis, subdural empyema)

Meningitis, noninfectious (eg, carcinomatous, chemical)

Obstructive hydrocephalus

Vascular disorders (eg, vascular malformations, vasculitis, venous sinus thrombosis)

Systemic disorders
Acute severe hypertension

Bacteremia

Fever

Giant cell arteritis

Hypercapnia

Hypoxia (including altitude sickness)

Viral infections

Viremia

Drugs and toxins
Analgesic overuse

Caffeine withdrawal

Carbon monoxide

Hormones (eg, estrogen)

Nitrates

Proton pump inhibitors

Table 2

Some Characteristics of Headache Disorders by Cause

Cause
Suggestive Findings
Diagnostic Approach

Primary headache disorders*

Cluster headache
Unilateral orbitotemporal attacks at the same time of day

Deep, severe, lasting 30–180 min

Often with lacrimation, facial flushing, or Horner syndrome; restlessness
Clinical evaluation

Migraine headache
Frequently unilateral and pulsating, lasting 4–72 h

Occasionally with aura, nausea, photophobia, sonophobia, or osmophobia

Worse with activity, preference to lie in the dark, resolution with sleep
Clinical evaluation

Tension-type headache
Frequent or continuous, mild, bilateral, and viselike occipital or frontal pain that spreads to entire head

Worse at end of day
Clinical evaluation

Secondary headache

Acute angle-closure glaucoma
Unilateral

Halos around lights, decreased visual acuity, conjunctival injection, vomiting
Tonometry

Encephalitis
Fever, altered mental status, seizures, focal neurologic deficits
MRI, CSF analysis

Giant cell arteritis
Age > 55

Unilateral throbbing pain, pain when combing hair, visual disturbances, jaw claudication, fever, weight loss, sweats, temporal artery tenderness, proximal myalgias
ESR, temporal artery biopsy, usually neuroimaging

Idiopathic intracranial hypertension
Migraine-like headache, diplopia, pulsatile tinnitus, loss of peripheral vision, papilledema
Neuroimaging (preferably MRI with magnetic resonance venography), followed by measurement of CSF opening pressure

Intracerebral hemorrhage
Sudden onset

Vomiting, focal neurologic deficits, altered mental status
Neuroimaging

Meningitis
Fever, meningismus, altered mental status
CSF analysis, often preceded by CT

Sinusitis
Positional facial or tooth pain, fever, purulent rhinorrhea
Clinical evaluation, sometimes CT

Subarachnoid hemorrhage
Peak intensity a few seconds after headache onset (thunderclap headache)

Vomiting, syncope, obtundation, meningismus
Neuroimaging, followed by CSF analysis if it is not contraindicated and imaging is not diagnostic

Subdural hematoma (chronic)
Sleepiness, altered mental status, hemiparesis, loss of spontaneous venous pulsations, papilledema

Presence of risk factors (eg, older age, coagulopathy, dementia, anticoagulant use, ethanol abuse)
Neuroimaging

Tumor or mass
Eventually altered mental status, seizures, vomiting, diplopia when looking laterally, loss of spontaneous venous pulsations or papilledema, focal neurologic deficits
Neuroimaging

* Primary headaches are usually recurrent.

Evaluation

Evaluation focuses on determining whether a secondary headache is present and checking for symptoms that suggest a serious cause. If no cause or serious symptoms are identified, evaluation focuses on diagnosing primary headache disorders.

History: History of present illness includes questions about headache location, duration, severity, onset (eg, sudden, gradual), and quality (eg, throbbing, constant, intermittent, pressure-like). Exacerbating and remitting factors (eg, head position, time of day, sleep, light, sounds, physical activity, odors, chewing) are noted. If the patient has had previous or recurrent headaches, the previous diagnosis (if any) needs to be identified, and whether the current headache is similar or different needs to be determined. For recurrent headaches, age at onset, frequency of episodes, temporal pattern (including any relationship to phase of menstrual cycle), and response to treatments (including OTC treatments) are noted.

Review of systems should seek symptoms suggesting a cause, including

Vomiting: Migraine, increased intracranial pressure

Fever: Infection (eg, encephalitis, meningitis, sinusitis)

Red eye and/or visual symptoms (halos, blurring): Acute angle-closure glaucoma

Visual field deficits, diplopia, or blurring vision: Ocular migraine, brain mass lesion, or idiopathic intracranial hypertension

Lacrimation and facial flushing: Cluster headache

Rhinorrhea: Sinusitis

Pulsatile tinnitus: Idiopathic intracranial hypertension

Preceding aura: Migraine

Focal neurologic deficit: Encephalitis, meningitis, intracerebral hemorrhage, subdural hematoma, tumor, or other mass lesion

Seizures: Encephalitis, tumor, or other mass lesion

Syncope at headache onset: Subarachnoid hemorrhage

Myalgias and/or vision changes (in people > 55 yr): Giant cell arteritis

Past medical history should identify risk factors for headache, including exposure to drugs, substances (particularly caffeine), and toxins (see Table 1: Headache: Disorders Causing Secondary Headache), recent lumbar puncture, immunosuppressive disorders or IV drug use (risk of infection); hypertension (risk of brain hemorrhage); cancer (risk of brain metastases); and dementia, trauma, coagulopathy, or use of anticoagulants or ethanol (risk of subdural hematoma).

Family and social history should include any family history of headaches, particularly because migraine headache may be undiagnosed in family members.

To streamline data collection, clinicians can ask patients to fill out an online headache questionnaire that covers most of the relevant medical history pertinent to diagnosis of headache; it is available at ProMyHealth. Patients may complete the questionnaire before their visit and bring the results with them.

Physical examination: Vital signs, including temperature, are measured. General appearance (eg, whether restless or calm in a dark room) is noted. A general examination, with a focus on the head and neck, and a full neurologic examination are done.

The scalp is examined for areas of swelling and tenderness. The ipsilateral temporal artery is palpated, and both temporomandibular joints are palpated for tenderness and crepitance while the patient opens and closes the jaw.

The eyes and periorbital area are inspected for lacrimation, flushing, and conjunctival injection. Pupillary size and light responses, extraocular movements, and visual fields are assessed. The fundi are checked for spontaneous venous pulsations and papilledema. If patients have vision-related symptoms or eye abnormalities, visual acuity is measured. If the conjunctiva is red, the anterior chamber and cornea are examined with a slit lamp if possible, and intraocular pressure is measured.

The nares are inspected for purulence. The oropharynx is inspected for swellings, and the teeth are percussed for tenderness.

Neck is flexed to detect discomfort, stiffness, or both, indicating meningismus. The cervical spine is palpated for tenderness.

Red flags: The following findings are of particular concern:

Neurologic symptoms or signs (eg, altered mental status, weakness, diplopia, papilledema, focal neurologic deficits)

Immunosuppression or cancer

Meningismus

Onset of headache after age 50

Thunderclap headache (severe headache that peaks within a few seconds)

Symptoms of giant cell arteritis (eg, visual disturbances, jaw claudication, fever, weight loss, temporal artery tenderness, proximal myalgias)

Systemic symptoms (eg, fever, weight loss)

Progressively worsening headache

Red eye and halos around lights

Interpretation of findings: If similar headaches recur in patients who appear well and have a normal examination, the cause is rarely ominous. Headaches that have recurred since childhood or young adulthood suggest a primary headache disorder. If headache type or pattern clearly changes in patients with a known primary headache disorder, secondary headache should be considered.

Most single symptoms of primary headache disorders other than aura are nonspecific. A combination of symptoms and signs is more characteristic (see Table 2: Headache: Some Characteristics of Headache Disorders by Cause).

Red flag findings suggest a cause (see Table 3: Headache: Matching Red Flag Findings with a Cause for Headache).

Table 3

Matching Red Flag Findings with a Cause for Headache

Suggestive Findings
Causes

Neurologic symptoms or signs (eg, altered mental status, confusion, neurogenic weakness, diplopia, papilledema, focal neurologic deficits)
Encephalitis, subdural hematoma, subarachnoid or intracerebral hemorrhage, tumor, other intracranial mass, increased intracranial pressure

Immunosuppression or cancer
CNS infection, metastases

Meningismus
Meningitis, subarachnoid hemorrhage, subdural empyema

Onset of headache after age 50
Increased risk of a serious cause (eg, tumor, giant cell arteritis)

Thunderclap headache (severe headache that peaks within a few seconds)
Subarachnoid hemorrhage

Combination of fever, weight loss, visual disturbances, jaw claudication, temporal artery tenderness, and proximal myalgias
Giant cell arteritis

Systemic symptoms (eg, fever, weight loss)
Sepsis, hyperthyroidism, cancer

Progressively worsening headache
Secondary headache

Red eye and halos around lights
Acute angle-closure glaucoma

Testing: Most patients can be diagnosed without testing. However, some serious disorders may require urgent or immediate testing. Some patients require tests as soon as possible. CT (or MRI) should be done in patients with any of the following findings:

Thunderclap headache

Altered mental status

Meningismus

Papilledema

Signs of sepsis (eg, rash, shock)

Acute focal neurologic deficit

Severe hypertension (eg, systolic > 220 mm Hg or diastolic > 120 mm Hg on consecutive readings)

In addition, if meningitis, subarachnoid hemorrhage, or encephalitis is being considered, lumbar puncture and CSF analysis should be done, if not contraindicated by imaging results.

Tonometry should be done if findings suggest acute narrow-angle glaucoma (eg, visual halos, nausea, corneal edema, shallow anterior chamber).

Other testing should be done within hours or days, depending on the acuity and seriousness of findings and suspected causes.

Neuroimaging, usually MRI, should be done if patients have any of the following:

Focal neurologic deficit of subacute or uncertain onset

Age > 50 yr

Weight loss

Cancer

HIV infection or AIDS

Change in an established headache pattern

Diplopia

ESR should be done if patients have visual symptoms, jaw or tongue claudication, temporal artery signs, or other findings suggesting giant cell arteritis.

CT of the paranasal sinuses is done to rule out complicated sinusitis if patients have a moderately severe systemic illness (eg, high fever, dehydration, prostration, tachycardia) and findings suggesting sinusitis (eg, frontal, positional headache, epistaxis, purulent rhinorrhea).

Lumbar puncture and CSF analysis are done if headache is progressive and findings suggest idiopathic intracranial hypertension (eg, transient obscuration of vision, diplopia, pulsatile intracranial tinnitus) or chronic meningitis (eg, persistent low-grade fever, cranial neuropathies, cognitive impairment, lethargy, vomiting, focal neurologic deficits).

Treatment

Treatment of headache is directed at the cause.

Geriatrics Essentials

New-onset headache after age 50 should be considered a secondary disorder until proven otherwise.

Key Points

Recurrent headaches that began at a young age in patients with a normal examination are usually benign.

Immediate neuroimaging is recommended for patients with altered mental status, seizures, papilledema, focal neurologic deficits, or thunderclap headache.

CSF analysis is required for patients with meningismus and usually, after neuroimaging, for immunosuppressed patients.

Patients with thunderclap headache require CSF analysis even if CT and examination findings are normal.