Charlin Syndrome

Charlin Syndrome

Charlin syndrome, also known as nasociliary neuralgia and Charlin-Sluder cephalgia, is an uncommon cause of head and face pain. As with most headache syndromes, the exact cause of the pain of Charlin syndrome is unknown. However, the pathogenesis of this uncommon cause of head and face pain is thought to be dysfunction of the nasociliary ganglion in a manner analogous to the dysfunction of the sphenopalatine ganglion thought to be the source of cluster headache. The pain of Charlin syndrome has a rapid onset to peak, with attacks lasting 45 to 60 minutes. In some patients, these attacks can be triggered by sensory stimulation of the affected areas. Although in many ways similar to cluster headache (e.g., retroorbital location of pain, profuse unilateral rhinorrhea, rapid onset to peak, and short duration of attacks), many dissimilarities also exist. In contrast to cluster headache, alcohol consumption does not appear to trigger attacks of Charlin syndrome and the seasonal and chronobiological patterns so characteristic of cluster headache do not seem to be a factor. Blockade of the sphenopalatine ganglion, which is so effective in the treatment of cluster headache, is of little value in the treatment of Charlin syndrome. Patients suffering from Charlin syndrome uniformly respond to daily nasociliary nerve blocks with local anesthetic, as described subsequently.

Comparison of Cluster Headache and Charlin Syndrome

Comparison FactorsCluster HeadacheCharlin Syndrome
Ocular and retroorbital locationYesYes
Rapid onset to peakYesYes
Severe intensityYesYes
Attacks occur in paroxysmsYesYes
Duration of attacks shortYesYes
Pain free between attacksYesYes
Significant rhinorrhea during attacksYesYes
Alcohol triggers attacksYesNo
Tactile trigger areasNoYes
Seasonal pattern of attacksYesNo
Chronobiological pattern of attacksYesNo
Significant eye inflammationNoYes
Responds to sphenopalatine ganglion blockYesNo
Responds to nasociliary blockNoYes

What are the Symptoms of Charlin Syndrome

Patients suffering from Charlin syndrome present with the complaint of severe paroxysms of ocular or retroorbital pain that radiates into the ipsilateral forehead, nose, and maxillary region. This pain is associated with voluminous ipsilateral rhinorrhea and congestion of the nasal mucosa and significant inflammation of the affected eye.

How is Charlin Syndrome diagnosed?

Magnetic resonance imaging (MRI) of the brain provides the best information regarding the cranial vault and its contents. MRI is highly accurate and helps identify abnormalities that may put the patient at risk for neurological disasters secondary to intracranial and brainstem pathological conditions, including tumors and demyelinating disease.

Magnetic resonance angiography (MRA) also may be useful in helping identify aneurysms, which may be responsible for the patient’s neurological findings.

In patients who cannot undergo MRI, such as a patient with a pacemaker, computed tomography (CT) is a reasonable second choice. Radionuclide bone scanning and plain radiography are indicated if fracture or bony abnormality such as metastatic disease is considered in the differential diagnosis.

Screening laboratory tests consisting of complete blood cell count, erythrocyte sedimentation rate, and automated blood chemistry testing should be performed if the diagnosis of Charlin syndrome is in question. Intraocular pressure should be measured if glaucoma is suspected.

Differential Diagnosis

Charlin syndrome is a clinical diagnosis supported by a combination of clinical history, normal physical examination, radiography, and MRI. Pain syndromes that may mimic Charlin syndrome include cluster headache, temporal arteritis, trigeminal neuralgia involving the first division of the trigeminal nerve, demyelinating disease, and chronic paroxysmal hemicrania.

Trigeminal neuralgia involving the first division of the trigeminal nerve is uncommon and is characterized by trigger areas and tic-like movements. Demyelinating disease is generally associated with other neurological findings, including optic neuritis and other motor and sensory abnormalities. The pain of chronic paroxysmal hemicrania lasts much longer than the pain of Charlin syndrome.


The treatment of Charlin syndrome is analogous to the treatment of trigeminal neuralgia.

The use of anticonvulsants such as carbamazepine and gabapentin represents a reasonable starting point. High-dose steroids tapered over 10 days also have been anecdotally reported to provide relief. For patients who do not respond to the previously mentioned treatments, daily nasociliary ganglion block with local anesthetic and steroid is a reasonable next step.

Underlying sleep disturbance and depression associated with the pain of supraorbital neuralgia are best treated with a tricyclic antidepressant compound, such as nortriptyline, which can be started at a single bedtime dose of 25 mg.


Failure to diagnose Charlin syndrome correctly may put the patient at risk if an intracranial pathological condition or demyelinating disease, which may mimic the clinical presentation of Charlin syndrome, is overlooked. MRI is indicated in all patients thought to have Charlin syndrome.

Failure to diagnose glaucoma or temporal arteritis, which also may cause intermittent ocular pain, may result in permanent loss of sight.

Clinical Pearls

Nasociliary nerve block via the medial orbital approach is especially useful in the diagnosis and palliation of pain secondary to Charlin syndrome.

Given the uncommon nature of this headache syndrome and its overlap with the symptoms of cluster headache and other neurological problems, including cavernous sinus thrombosis and intracranial and retroorbital tumors, Charlin syndrome must remain a diagnosis of exclusion.

All patients suspected to have Charlin syndrome require MRI of the brain with and without gadolinium contrast material and thorough ophthalmological and neurological evaluation. Nasociliary nerve block via the medial orbital approach should be performed only by clinicians familiar with the regional anatomy.


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