Peer Reviewed
Arnold Nerve Reflex: An Uncommon Cause of Persistent Cough
AUTHOR:
Marika Alois, MD
AFFILIATION:
Division of General Internal Medicine, Department of Medicine, University of Florida College of Medicine, Gainesville, Florida
CITATION:
Alois M. Arnold nerve reflex: an uncommon cause of persistent cough. Consultant. 2022;62(9):e8-e9. doi:10.25270/con.2021.10.00012
Received June 10, 2021. Accepted July 29, 2021. Published online October 28, 2021.
DISCLOSURES:
The authors report no relevant financial relationships.
CORRESPONDENCE:
Marika Alois, MD, University of Florida College of Medicine, 4197 NW 86th Terrace, Gainesville, FL 32606 (marika.alois@medicine.ufl.edu)
A 73-year-old woman presented to our primary care office with a 1-week history of cough. Her cough was nonproductive and not associated with any sinonasal congestion or postnasal drainage.
History. She had a history of gastroesophageal reflux disease (GERD), for which she was taking omeprazole, and asymptomatic mild centrilobular emphysema.
She had no sick contacts and no preceding viral illness. She is a former smoker with a 30-pack–year smoking history and underwent a low-dose computed tomography scan of her chest 3 months prior to presentation, results of which showed no findings concerning for malignancy. She had no accompanying fever, chills, weight loss, malaise, or hemoptysis.
She had tried taking an old prescription of benzonatate with no relief.
Physical examination. The patient was afebrile, with a normal blood pressure, pulse rate, respiratory rate, and oxygen saturation on room air. She appeared well and in no acute distress. Her nasal turbinates were swollen with rhinorrhea present, but she had no sinus tenderness or purulent nasal discharge. Her oropharynx was erythematous but without posterior pharyngeal exudates. Her breathing was unlabored and lungs were clear to auscultation bilaterally.
A presumptive diagnosis of upper airway cough syndrome was made, and the patient was advised to initiate saline nasal irrigation, an intranasal steroid, and an oral antihistamine. She was also prescribed guaifenesin with codeine cough syrup to use as needed. She returned 2 weeks later requesting a refill of the cough syrup. The saline nasal irrigation and intranasal steroid had not impacted her cough. She was again prescribed guaifenesin with codeine cough syrup, and when she returned 1 week later with persistent symptoms, an otoscopic examination was performed. Results of the examination showed a right-sided cerumen impaction. Her ear was irrigated to remove the cerumen and her cough completely resolved within 2 to 3 days of the procedure without further intervention.
Discussion. Pathophysiologically, stimulation of structures such as the upper and lower airways and distal esophagus that are innervated by the vagus nerve results in cough. The most common causes of persistent cough are upper airway cough syndrome, asthma, nonasthmatic eosinophilic bronchitis, and GERD.1 A less commonly considered cause of cough is the ear-cough reflex, or Arnold nerve reflex. This reflex involves stimulation of cough via manipulation of the auricular branch of the vagus nerve, which innervates the posteroinferior aspects of the external auditory canal.2 Physical stimuli such as impacted cerumen, hair, and foreign bodies in this area may be inciting factors. The Arnold nerve reflex is not universally present, however. In a study that used a cotton-tipped applicator to stimulate the external auditory canal to elicit the reflex, it was found to be present in only 2% of healthy adults and 25.5% of adults with chronic cough.3
In our case, our patient was assessed for common causes of cough and treated presumptively for upper airway cough syndrome. When symptoms proved refractory, an otoscopic examination was performed and cerumen impaction was found and addressed. Shortly thereafter, her cough resolved in the absence of other interventions, arguing strongly for cerumen-triggered Arnold nerve reflex as the cause for her symptoms.
This case report should serve as a reminder to examine the ears of our patients presenting with cough to assess for and address any external auditory conditions that may be contributing.
References
1. Irwin RS, Baumann MH, Bolser DC, et al. Diagnosis and management of cough executive summary: ACCP evidence-based clinical practice guidelines. Chest. 2006;129(1 Suppl):1S-23S. https://doi.org/10.1378/chest.129.1_suppl.1s
2. Gupta D, Verma S, Vishwakarma SK. Anatomic basis of Arnold's ear-cough reflex. Surg Radiol Anat. 1986;8(4):217-220. https://doi.org/10.1007/bf02425070
3. Dicpinigaitis PV, Kantar A, Enilari O, Paravati F. Prevalence of Arnold nerve reflex in adults and children with chronic cough. Chest. 2018;153(3):675-679. https://doi.org/10.1016/j.chest.2017.11.019