Headache and facial pain are common complaints in the emergency and outpatient setting. The lifetime prevalence of headache is greater than 90%.  Most patients who present with headache have 1 of the following 3 main headache syndromes: migraine, cluster headache, or tension headache. 
However, headache and facial pain can have numerous other etiologies that are important for the clinician to consider. The reader is referred to the International Headache Society (IHS) classification for an exhaustive compilation of all headache and facial pain etiologies.
In the evaluation of headache and facial pain, the primary goal for the otolaryngologist is to make a distinction between sinogenic and nonsinogenic causes of headache and facial pain.
The trigeminal nerve (cranial nerve V) and its constituent 3 major branches provide most somatosensory innervation to the head and face region. The trigeminal nerve originates in the lateral pons then divides into the following 3 divisions from the gasserian ganglion: the ophthalmic (V-1), the maxillary (V-2), and the mandibular (V-3) divisions.
The ophthalmic division (V-1) provides sensory innervation to most of the upper third of the head and face, including (but not limited to) the skin of the eyelids, eyebrow, forehead, and nose and part of the mucous membranes of the nasal cavity.  Ethmoidal branches supply the mucous membranes of the ethmoid sinuses. An intracranial branch called the tentorial nerve of Arnold supplies the tentorium, superior surface of the transverse and straight dural sinuses, and the inferior two thirds of the falx cerebri. 
The maxillary division (V-2) innervates several key areas in the midface region including the upper teeth, the floor and anterior region of the nasal cavity, and the skin of the lateral nose and malar region. The sphenopalatine branches innervate the lining of the maxillary sinuses, and the middle meningeal branch supplies portions of the floor of the middle fossa dura. 
The mandibular branch (V-3) supplies the teeth and gums of the mandible, the skin of the lower face, the temporomandibular joint (TMJ) and also the dura of the lateral portion of the middle fossa and most of the cranium. 
The trigeminal system is the main source for sensory innervation to the supratentorial dura, venous sinuses, and meningeal arteries. The 7th, 9th, and 10th cranial nerves also contain somatosensory pain fibers that synapse with trigeminal pain axons. 
Sinogenic Facial Pain and Headache
The International Headache Society (IHS) classification system lists the following criteria for a diagnosis for sinus headache: 
- Frontal headache that is accompanied by pain in one or more regions of the face, ears, or teeth and that fulfills criteria C and D
- Clinical, nasal endoscopic, or CT and/or MRI and/or laboratory evidence of acute or acute-on-chronic rhinosinusitis
- Headache and facial pain that develop simultaneously with the onset or acute exacerbation of rhinosinusitis
- Headache, facial pain, or both that resolve within 7 days of remission or successful treatment of acute or acute-on-chronic rhinosinusitis
Most sinonasal pain is referred and is deep, aching, and usually nonpulsatile. The location of pain can help localize which sinus may be particularly involved, as follows: 
Frontal sinus - Frontal, vertex, and retro-orbital pain
Maxillary sinus - Malar region and upper teeth pain
Ethmoid sinus - Nasion and retro-orbital pain and pain that radiates to the temporal area
Sphenoid sinus - Vertex, occipital, frontal, and retro-orbital pain
Patients with facial pain secondary to acute sinusitis have coexisting symptoms such as nasal obstruction, hyposmia, or purulent nasal discharge and have endoscopic signs of disease such as purulent drainage, inflammation, and edema. [8, 9]
Pain severity and radiographic disease severity are not related in patients with sinusitis. 
Treatment of acute sinusitis consists of antibiotics with systemic or topical decongestants, analgesics, and aggressive hydration. Antibiotic treatment usually consists of amoxicillin or a macrolide antibiotic for 10-14 days. Patients who are poorly responsive, have continued disease at the end of treatment, and those with acute-on-chronic sinusitis may need treatment with second-line medications such as amoxicillin/clavulanate, second- or third-generation cephalosporins, fluoroquinolones, or clindamycin.
Endoscopic sinus surgery (ESS) should be considered for chronic rhinosinusitis in which medical therapy has failed. Studies have shown that facial pain and pressure improve in 56-77% of patients after ESS. Some studies have also reported improvement in facial pain in patients who undergo ESS for nonsinogenic headache and facial pain. However, most of these patients have recurrence of pain within 9 months. 
A 2015 update of the clinical practice guideline for adult sinusitis, from the American Academy of Otolaryngology-Head and Neck Surgery Foundation, strongly recommends that clinicians differentiate acute bacterial rhinosinusitis from acute rhinosinusitis resulting from viral upper respiratory infections or from noninfectious causes and that a clinical diagnosis of chronic rhinosinusitis be confirmed by objectively documenting sinonasal inflammation. The guideline also recommends that clinicians do the following  :
Either offer watchful waiting (without antibiotics) or prescribe initial antibiotic therapy for adults with uncomplicated acute bacterial rhinosinusitis
Prescribe amoxicillin with or without clavulanate as ﬁrst-line therapy for 5-10 days (if a decision is made to treat acute bacterial rhinosinusitis with an antibiotic)
Reassess the patient to confirm acute bacterial rhinosinusitis, exclude other causes of illness, and detect complications if the patient worsens or fails to improve with the initial management option by 7 days after diagnosis or worsens during the initial management
Distinguish chronic rhinosinusitis and recurrent acute rhinosinusitis from isolated episodes of acute bacterial rhinosinusitis and other causes of sinonasal symptoms
Assess the patient with chronic rhinosinusitis or recurrent acute rhinosinusitis for multiple chronic conditions that would modify management, such as asthma, cystic fibrosis, immunocompromised state, and ciliary dyskinesia
Confirm the presence or absence of nasal polyps in a patient with chronic rhinosinusitis
Recommend saline nasal irrigation, topical intranasal corticosteroids, or both for symptom relief of chronic rhinosinusitis
Sinus mucoceles (mucus-retention cysts) are chronic, slow-growing, cystic lesions. Mucoceles can be a source of pain when they are large enough to cause pressure against the bony walls of the sinus. Maxillary mucocele can cause sinusitis through ostiomeatal obstruction. Frontoethmoidal mucocele is the most clinically significant and can cause frontal headache and orbital pain. Sphenoethmoidal mucocele can cause occipital, vertex, or deep nasal pain. Treatment consists of endoscopic surgical removal or marsupialization. 
Mucosal contact points within the nasal cavity have also been implicated as a cause for rhinogenic facial pain. Typically, the resolution of symptoms after the placement of a vasoconstrictive agent at a contact point was diagnostic of contact point pain. Controversy exists regarding this etiology for facial pain. In some studies, the prevalence of contact points has been shown to be equal between symptomatic and asymptomatic patients.  Conversely, other studies have shown improvements in the pain scores of patients who underwent surgery for a diagnosis of mucosal contact point headache. 
Primary Headache Syndromes
A tension headache causes mild-to-moderate pain that is typically bilateral and nonpulsatile. Associated features are usually absent, but the headache may improve with physical activity. The most common triggers is stress.  Depression and anxiety also play a role in tension and cluster headaches. [17, 18]
Relaxation training, stress management, and counseling have been shown to be beneficial. [19, 20] If frequent headache occurs, antidepressant medication is warranted. Acute attacks can be treated with limited usage of analgesics. 
Migraine headache is typically considered to be a throbbing, unilateral pain, although up to 40% may have bilateral symptoms.  It is 3 times more common in women, and a positive family history often exists.  Classic migraine occurs in 25% of patients with associated symptoms such as nausea, aura, and photophobia. Migraine symptoms can also overlap with those more characteristic of tension, cluster, or so-called sinus headache. Nonsteroidal anti-inflammatory drugs (NSAIDs) are first-line agents for acute attacks. If these are ineffective, then specific medications such as triptans and dihydroergotamine are used. Preventative agents can also be used for those who experience chronic migraine, including beta blockers, tricyclic antidepressants, and anticonvulsants. 
Cluster headache typically manifests as minutes to hours of severe unilateral temporal headache that occurs in grouped attacks over a period of weeks to months.  Periorbital pain with associated rhinorrhea or lacrimation occurs. Cluster headaches most commonly occur in men aged 30-40 years. Acute treatment is oxygen at 7-12 L/min over 15 minutes. The abortive agent of choice is subcutaneous sumatriptan. Preventative agents include corticosteroids or ergotamine titrate. 
Secondary Facial Pain and Headache
Headache and facial pain can be a presenting sign of a cerebrovascular disorder including, but not limited to, stroke and transient ischemic attack, intracerebral hemorrhage, subarachnoid hemorrhage, arteriovenous malformation, cerebral venous thrombosis, carotid artery dissection and vertebral artery dissection, and postcarotid endarterectomy headache. 
Temporal arteritis is a chronic vasculitis of medium- and large-sized vessels. Headache is the presenting symptom in 72% of patients.  The pain is intense, unilateral or bilateral, and is associated with tenderness over the temporal arteries. Diplopia and jaw claudication can occur. Temporal artery biopsy is performed for diagnosis. Treatment consists of oral corticosteroids. 
Oral cavity and craniomandibular pain
Pain of dental origin can be referred to many areas of the head and face. Facial pain of dental origin is often caused by caries that progress to infection of the pulp or apical abscess or periodontal disease. 
Temporomandibular joint (TMJ) disorders are known to cause facial pain and headache. Females with TMJ disorders outnumber males, and the onset is in those aged 30-50 years. The TMJ is a diarthrodial joint between the mandibular condyle and the glenoid fossa of the temporal bone. A fibrocartilaginous disc that is attached to the joint capsule allows the condyle to perform both rotational and translational movements.
The 3 main categories of TMJ syndrome are chronic myofascial pain, internal derangement, and degenerative joint disease (DJD). 
Chronic myofascial pain is most common and is similar in nature to fibromyalgia. The pain is unilateral, dull in character, and localized to the preauricular region. Pain is exacerbated by chewing, yawning, or the stimulation of certain trigger points that are usually located with palpable bands of muscle. Treatment consists of soft diet, analgesics, corticosteroids, local anesthetic blocks, muscle stretching, and treatment of psychological factors. 
Internal derangement usually consists of an anterior displacement of the disc. A dull preauricular pain with joint tenderness and an audible or palpable joint “click” is present upon examination.  Treatment consists of a soft diet, orthotic appliances, and physical therapy.  Surgical management can be used in refractory cases, but this is becoming less common.
DJD is essentially osteoarthritis of the joint and should be treated with a soft diet and NSAIDs.
The remaining categories of secondary headache include headaches attributed to head trauma and neck trauma, nonvascular intracranial disorders (eg, hydrocephalus, tumor), substance abuse or withdrawal (eg, caffeine withdrawal), infection (eg, meningitis), homeostasis disorders (eg, hypoxia, hypertension), disorders of cranial and facial structures (eg, orbital pain, otalgia, cervical spine disorders), and psychiatric causes.
Facial neuralgias are often sudden, lancinating pains that are unilateral and limited to the distribution of the affected cranial nerve.  Studies have shown positive results in treating cranial neuralgia with botulinum toxin. 
This is the most common cranial neuralgia, with an incidence of 5 per 100,000.  It is a brief, paroxysmal, unilateral, stabbing pain in the distribution of one or more of the branches of the fifth cranial nerve. The mandibular branch is most commonly affected. Pain is often triggered by minimal stimulation of the affected area, oftentimes in the location of a “trigger zone.” Most cases are idiopathic, but secondary trigeminal neuralgia (TN) can be caused by vascular or neoplastic compression of the gasserian ganglion or infiltrating lesions.  Treatment initially consists of carbamazepine or other antiepileptic drugs.  Surgical microvascular decompression and also the use of gamma knife radiation have been shown to treat cases caused by compression of the trigeminal nerve from pontine vessels. 
A study by Nanda et al suggested that microvascular decompression has a higher rate of success in producing total long-term pain relief than does gamma knife radiosurgery. The study, which included 49 patients treated with gamma knife radiosurgery and 20 patients treated with microvascular decompression, found that at last follow-up (median 5.3 years), 85% of the microvascular decompression patients were experiencing total pain relief, compared with 45% of the gamma knife patients. 
This is a paroxysmal pain that originates in the tonsillar fossa or tongue base region. The pain can be provoked by swallowing, chewing, yawning, or talking.  Hypotension, bradycardia, or syncope can also occur. The etiology is thought to be from intracranial vascular compression of the ninth cranial nerve as it exits the medulla. Initial treatment consists of carbamazepine. 
This occurs in the suboccipital region following the distribution of the greater or lesser occipital nerves. It can occur secondary to trauma to the nerves, arthritic changes to the cervical spine, or compression from tumor. Anticonvulsants, antidepressants, local nerve blocks, and surgical cervical root sectioning have all been described as treatments for idiopathic cases. [26, 30]
Nervus intermedius neuralgia
This is a lancinating pain in the somatosensory branch of the seventh cranial nerve. The pain is a deep pain in the external auditory canal triggered by stimulation of the canal or by swallowing or talking. Medical management is similar to that for trigeminal neuralgia. 
Central and Idiopathic Facial Pain and Headache
Two main idiopathic disorders that cause headache and facial pain are midfacial segment pain and atypical facial pain. 
Midfacial segment pain
This is a form of tension-type headache of the midface. Pain is a symmetric pressure sensation in the nasion, nasal dorsum, periorbital, or malar region. Hyperesthesia of the skin and soft tissues is also found. Treatment consists of low-dose amitriptyline at 10 mg for 6 months, which may take up to 6 weeks to show effect. [32, 33]
Atypical facial pain
This is also known as persistent idiopathic facial pain, as classified by the International Headache Society (IHS). The pain is constant, deep, and ill defined, usually crossing recognized dermatomes. The distribution is often unilateral. It occurs most commonly in women older than 40 years. The pain may alter in location, and psychological factors may play a role. The treatment is similar to that for midfacial segment pain. 
Workup and Treatment
The onset, duration, quality, location, and exacerbating and relieving factors of the pain are important points to elicit. The clinician should ask about any associated factors such as aura, tearing, rhinorrhea, nausea, and photophobia. A history of rhinitis, recurrent or acute sinusitis, purulent nasal discharge, and hyposmia should be elicited. Comorbid illness such as diabetes, hypertension, dental disease, psychiatric illness, or a history of head or facial trauma or prior surgery should be questioned. A review of systems should include constitutional symptoms such as weight loss, fatigue, fevers, and gastrointestinal complaints. The patient should provide a full list of his or her medications, as overmedication of headaches is a significant risk.  A social history should include a history of substance abuse, caffeine use, and use of alcohol or tobacco. A family history of migraine, other headache, or head and neck cancer should be noted.
A thorough head and neck examination should be performed, including testing of the cranial nerves, palpation for points of tenderness, trigger points, jaw clicks, and dental pain. If a rhinogenic source is a concern, nasal endoscopy looking for purulence, edema, inflammation, trauma, and tumor should be performed. A neurologic examination should also be performed.
See the list below:
Noncontrast CT of the sinuses with axial and coronal sections is the criterion standard for the radiographic diagnosis of sinusitis or possible rhinogenic causes of pain.
MRI is useful for the evaluation of temporomandibular joint (TMJ) disorders, specifically for internal derangement.
MRI, and/or magnetic resonance angiography (MRA) of the brain is useful to evaluate for intracranial pathology (tumor, hydrocephalus) and vascular sources of headache. It also is used to assess for microvascular compression of cranial nerve roots.
Treatment methods for individual etiologies of headache and facial pain are discussed above. Depending on the clinical suspicion of the possible etiologies of facial pain and headache, the appropriate consultations should be made. For concerns of head and neck lesions or sinus-related headache, an otolaryngologist should be consulted. If a primary headache syndrome or a cranial neuralgia is of concern, the patient should be evaluated by a neurologist. Dentists and oral surgeons should be involved in the care for a patient with a dental or craniomandibular cause of pain. In some cases, a psychiatry referral is appropriate. Any concern for intracranial hemorrhage or meningitis should be evaluated in the emergency setting.