Hypersensitivity drives chronic cough

By Mardi Chapman

8 Oct 2019

Don’t dismiss chronic cough as “just a cough” as its consequences including incontinence, sleep and social disruption can be distressing for patients.

Professor Alyn Morice, head of respiratory medicine and the Centre for Cardiovascular & Metabolic Research at the University of Hull, told a full session at the 2019 ERS Congress that chronic refractory cough was often associated with a poor quality of life.

He said it was more common than asthma and affected all ages but mostly middle-aged women.

Professor Morice, who led the development of the recent ERS guidelines on the diagnosis and treatment of chronic cough in adults and children, said hypersensitivity of the vagus nerve was the main underlying cause of chronic cough.

However in children, chronic cough was best considered as a symptom of an underlying disease.

The guidelines recommend a fairly simply work up including a detailed history with the patient-reported Hull Airway Reflux Questionnaire helpful in directing the conversation.

He warned about one in ten patients were found to be using an angiotensin converting enzyme (ACE) inhibitor, which can increase hypersensitivity.

An examination, spirometry and chest X-ray could also help exclude differential diagnoses such as malignancy, infection or a foreign body inhalation

The impact of cough should be assessed with a 0-10 global score.

While there was a general lack of high quality evidence, the guidelines recommended short (2-4 weeks) sequential therapeutic trials of the following anti-asthma agents:

  • Inhaled corticosteroids
  • Anti-leukotrienes
  • ICS and long acting bronchodilator combination.

Professor Morice said antacids do not work unless patients have peptic reflux.

There was currently insufficient evidence to recommend the routine use of macrolides for their pro-motility activity however a one-month trial may be considered for the cough of chronic bronchitis refractory to other therapy.

In adults only, there was moderate evidence for neuromodulators including low-dose, slow-release morphine and gabapentin or pregabalin.

Antibiotics may be trialled in children with a wet cough but there was to date only low quality evidence.

P2X3 blockers had shown some promise in phase 2 studies.

Professor Morice said there was some evidence for a non-pharmacological approach but only when cough control therapy was delivered by skilled physiotherapists or speech pathologists.

He highlighted the work of Australian Dr Anne Vertigan, a speech pathologist from the Hunter Medical Research Institute who specialises in chronic cough.

Read her recent review article on a speech pathology intervention.

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