An uncommon cause of chronic cough is laryngeal sensory neuropathy. This occurs when the larynx suffers an injury and becomes hypersensitive to the slightest irritant resulting in a chronic dry cough. The same medications prescribed for other neuropathic conditions (such as painful diabetic neuropathy) are often effective in suppressing cough.
The typical patient has been suffering from the condition for some time and seen a few doctors, perhaps been diagnosed with a “postnasal drip,” allergy, reflux or asthma but does not reliably respond to any medication. Their frustration level is high. The cough is interfering with their social life, sleep and work performance.
History:
- Dry cough lasting for seconds to minutes and sometimes longer
- Throat clearing
- Cough has been present for months or even years.
- Abrupt symptom onset that may follow viral illness (or sometimes surgery)
- Does not fit the pattern of whooping cough
- Diagnostic tests for asthma, allergy and reflux are normal
- Patient is not responding to maximal therapy for other conditions related to cough
Diagnosis:
- High index of suspicion
- Videolaryngoscopy (which is often normal)
- Response to medications effective in neuropathy
- EMG studies (response of the larynx to small electrical stimuli) have been suggested but many patients with this condition have a normal EMG
Treatment: Response to medication is sometimes apparent within a day or two.
- Low dose antidepressants such as Elavil (Amitriptyline)
- Seizure medications such as Neurontin (Gabapentin)
Prognosis:
Most patients can taper off medications although some need to be on the medications long term and sometimes in combination. However, the condition can flare again with the onset of a cold. The good news is that the sooner the effective drug is started, the better the response and the shorter the duration of the cough.
Dr. Stadtmauer has treated many chronic cough patients with success. To see a representative case with video laryngoscopy, click here.