Charlin Syndrome – 8 Interesting Facts, Symptoms, Diagnosis, Treatment

What is Charlin Syndrome?

• Charlin’s syndrome is a very rare pathological condition, resulting from neuralgia of the nasociliary nerve.
• It is also called nasal nerve syndrome, nasociliaris nerve syndrome, and nasociliary syndrome.
• Some authors have referred to it as nasociliary neuralgia.
• In this syndrome, touching the outer aspect of one nostril causes a lancinating pain, which mainly radiates to the eyebrow, orbit, or into the nose or jaw, and is also accompanied by lacrimation, conjunctival infection, nasal congestion, sneezing, and redness of the skin on the forehead.

Interesting Facts of Charlin Syndrome

1. Charlin syndrome, also known as nasociliary neuralgia and Charlin-Sluder cephalgia, is an uncommon cause of head and face pain.
2. As with most headache syndromes, the exact cause of the pain of Charlin syndrome is unknown.
3. 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.
4. The pain of Charlin syndrome has a rapid onset to peak, with attacks lasting 45 to 60 minutes.
5. In some patients, these attacks can be triggered by sensory stimulation of the affected areas.
6. 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.
7. 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.
8. 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 Factors	Cluster Headache	Charlin Syndrome
Ocular and retroorbital location	Yes	Yes
Unilateral	Yes	Yes
Rapid onset to peak	Yes	Yes
Severe intensity	Yes	Yes
Attacks occur in paroxysms	Yes	Yes
Duration of attacks short	Yes	Yes
Pain free between attacks	Yes	Yes
Significant rhinorrhea during attacks	Yes	Yes
Alcohol triggers attacks	Yes	No
Tactile trigger areas	No	Yes
Seasonal pattern of attacks	Yes	No
Chronobiological pattern of attacks	Yes	No
Significant eye inflammation	No	Yes
Responds to sphenopalatine ganglion block	Yes	No
Responds to nasociliary block	No	Yes

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?

• The diagnosis is confirmed by application of a local anesthetic to block external nasal nerve (by injection into the nose), anterior ethmoidal nerve (with intranasal applicator) or nasociliary nerve (by injection through medial orbital route), during paroxysms of headache
• 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.

The diagnostic criteria for Charlin’s syndrome

A. Stabbing pain lasting seconds to hours on one side of the nose, radiating upwards to the medial frontal region and fulfilling criteria B and C. In a case, the pain was restricted to patient’s left side of the nose radiating to the forehead and the left eye. Each episode of stabbing pain lasted for 10-45 min.

B. Pain precipitated on touching the lateral aspect of the ipsilateral nostril. Similarly, touching the patient’s left side of the nose generated lancinating pain.

C. Pain abolished by block or section of the nasociliary nerve, or by the application of cocaine to the nostril on the affected side. In our case, the pain subsided with a nasociliary nerve block.

Differential Diagnosis

Pain syndromes that may mimic Charlin syndrome include

• Cluster headache
• Temporal arteritis
• Trigeminal neuralgia involving the first division of the trigeminal nerve
• Demyelinating disease
• Chronic paroxysmal hemicrania

Charlin syndrome is a clinical diagnosis supported by a combination of clinical history, normal physical examination, radiography, and MRI.

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.

How is this condition treated?

• 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.

What research says about Charlin Syndrome?

There are some rare but probable devastating complications following any rhinoplasty.

Charlin syndrome is a typical one.

It is completely related to the external nasal nerve.

A study presented a report of a 21-year-old female with signs and symptoms of Charlin’s syndrome, persisting for 4 years after a routine septorhinoplasty operation.

Surgery was uneventful and the patient underwent bony septal resection and caudal septal relocation.

Osteotomy was internal low to low and external transverse bilaterally.

Overall, a routine septorhinoplasty was executed.

Everything went well postoperatively, until 4 months after surgery, when some irritating symptoms developed and gradually intensified.

Clinical Pearls

• The medial orbital approach to nasociliary nerve block is very helpful in diagnosing and treating Charlin syndrome-related pain.
• Charlin syndrome needs to be treated as an exclusion diagnosis due to its rarity, similarity to cluster headache symptoms, and overlap with other neurological conditions like intracranial and retroorbital tumors, cavernous sinus thrombosis, and other neurological disorders.
• A comprehensive ophthalmological and neurological examination, as well as a brain MRI with and without gadolinium contrast material, are necessary for all patients suspected of having Charlin syndrome. Only physicians who are knowledgeable with the regional anatomy should do a nosociliary nerve block using the medial orbital route.