What are the symptoms and treatment options for Arnold's nerve (greater auricular nerve) issues?

Arnold's Nerve (Auricular Branch of the Vagus Nerve)

What is Arnold's Nerve?

Arnold's nerve is the auricular branch of the vagus nerve that innervates the external auditory canal (ear canal), and when stimulated, can trigger a reflex cough in susceptible individuals. 1

The nerve emerges from the superior ganglion of the vagus nerve and runs through the jugular foramen to the mastoid canaliculus, ultimately providing sensory innervation to the postero-inferior and antero-inferior walls of the external acoustic meatus. 2

Clinical Presentation and Symptoms

Arnold's Ear-Cough Reflex

• The reflex occurs in approximately 2-3% of the general healthy population (both adults and children). 1, 3
• In adults with chronic cough, the prevalence dramatically increases to 23-26%, representing an 11-fold higher prevalence compared to healthy individuals. 4, 3
• The reflex is bilateral in only 0.3-2% of cases; most patients experience unilateral symptoms. 1, 2
• Women are affected 2-3 times more frequently than men among chronic cough patients (29-32% vs 10-13%). 4, 3

Triggering Mechanisms

The cough reflex can be elicited by:

• Mechanical stimulation of the ear canal with a cotton-tip applicator inserted 3-5 mm for 2-3 seconds 1
• Palpation of the postero-inferior wall of the external acoustic meatus (most common site) 2
• Presence of foreign material, hair, or cerumen resting on the ear drum 1
• The reflex typically occurs within 10 seconds of stimulation 4, 3

Associated Conditions

In children with chronic cough, Arnold's reflex prevalence remains at 2-3% (similar to healthy children), suggesting this is NOT a significant cause of pediatric chronic cough. 1, 4, 3

In adults with respiratory disease but without chronic cough, the prevalence remains at 2%, indicating the reflex is specifically associated with chronic cough rather than lung disease itself. 4

Diagnostic Approach

Clinical Examination

• Always examine the ears in any patient presenting with chronic cough. 1
• Test for the reflex by inserting a cotton-tip applicator 3-5 mm into the external auditory canal for 2-3 seconds on each side 1
• Cough occurring within 10 seconds indicates a positive Arnold's nerve reflex 4, 3
• Remove any visible foreign material, hair, or cerumen from the ear canal 1

Important Caveat

Despite the dramatic increase in reflex prevalence among adults with chronic cough, Arnold's nerve is still a very rare cause of childhood chronic cough in clinical practice. 1 The guideline emphasizes this point explicitly for pediatric patients.

Treatment Options

For Arnold's Nerve-Related Chronic Cough

Gabapentin has been successfully used to treat refractory chronic cough associated with Arnold's nerve reflex hypersensitivity. 5

• Gabapentin addresses the underlying sensory vagal neuropathy mechanism 5
• Treatment targets both the chronic cough and the Arnold's nerve reflex hypersensitivity simultaneously 5
• This approach is based on the understanding that the reflex represents vagal hypersensitivity as part of Cough Hypersensitivity Syndrome 4, 3, 5

For Great Auricular Neuralgia (Different Nerve)

If the question pertains to the great auricular nerve (C2-C3 nerve providing sensation to pre-auricular region, jaw angle, and mastoid):

• Nerve blocks provide dramatic pain improvement in all treated patients 6
• Serial nerve blocks can be continued successfully for 2-5 years 6
• Nerve stimulators represent an alternative for patients transitioning from blocks 6
• Pain is typically paroxysmal stabbing, provoked by head turning, neck touching, or jaw movement 6

Underlying Mechanism: Cough Hypersensitivity Syndrome

The markedly increased prevalence of Arnold's nerve reflex in adults (but not children) with chronic cough supports the concept of Cough Hypersensitivity Syndrome (CHS), where vagal hypersensitivity underlies chronic refractory cough. 4, 3, 5

• CHS appears to be an acquired condition rather than congenital, possibly triggered by viral respiratory infection or environmental factors 4, 3
• The absence of increased prevalence in children suggests the hypersensitivity develops over time 4, 3
• This represents a sensory neuropathy of the vagus nerve 5

Key Clinical Pitfalls

• Do not assume Arnold's nerve is a common cause of chronic cough in children—prevalence remains at baseline 2-3% 1, 4
• A negative history does not rule out ear-related causes; physical examination is essential 1
• The reflex may have a latent period before cough occurs 2
• Do not confuse Arnold's nerve (auricular branch of vagus) with the great auricular nerve (C2-C3 cervical nerve)—these are distinct structures with different clinical presentations 6, 2