Chronic Cough

Introduction 

• Chronic cough is very common, affecting 10% of the population at some point in life.
• The chronic cough algorithm covers all available treatments for chronic cough symptom. 
• The algorithm supports trials of treatment in people with chronic cough symptom, but no other  symptoms or signs to suggest an respiratory illness, and a normal Chest X-ray.
• There are no additional treatments available for chronic cough symptom, beyond those detailed within. See further details below under 'Who to refer/Who not to refer'.

Key Considerations

• Acute cough, lasting less than 8 weeks, is usually associated with acute bacterial or viral bronchitis, or other respiratory infections.
• A new or changed cough may be the presenting symptom of a respiratory illness, particularly lung cancer. A new or changed cough that is unexplained and persistent (more than 3 weeks), should prompt a respiratory examination, and a chest X-ray. 
• Chronic cough is a cough lasting more than 8 weeks. The character of the cough is not helpful in differentiating the cause of the cough. Very common triggers for chronic cough are noxious stimuli (gastric fluid, smoke, particulates, hyper- or hypo-tonicity). A very common presentation is a chest infection that resolved with time, but the cough persisted long term, beyond the expectation for ‘post-viral cough’.
• It is common to elicit a history of attacks of coughing after:
  • Laughing
  • Talking on the telephone
  • Moving from a warm environment to a cold environment, or vice versa
  • Eating
  • Coming into contact with strong smells (perfumes, flowers, food aromas)
• The presence or absence of these features does not help in determining the likely aetiology.
• A chronic cough is usually secondary to cough hypersensitivity, a heightened response to exposure to low levels of thermal, chemical or mechanical stimulation.
• The mechanisms of cough hypersensitivity are not fully understood.
• Chronic productive cough should be investigated and managed considering the possibility of chronic bronchial infection, and bronchiectasis.

Pharmacological Management of Chronic Cough (>8 weeks) is outlined in the linked algorithm with further information below. 

Smoking and vaping. All patients with chronic cough who smoke, or vape, should be strongly encouraged to stop smoking and directed to smoking cessations support services.

Asthma/Eosinophilic Bronchitis. What was previously referred to as ‘cough variant asthma’, is now more commonly referred to as eosinophilic bronchitis. The treatment is inhaled corticosteroids, to which this form of cough is usually very sensitive. Cough may be the only presenting symptoms of the full syndrome of asthma, so a thorough history should be sought. A predominantly nocturnal cough, and any history of wheeze and breathlessness should prompt assessment for asthma.

COPD. Cough is a common presenting complaint of COPD. Management is: smoking cessation; LABA/LAMA with consideration of ICS; referral to pulmonary rehabilitation.

Reflux Associated Cough. The role of reflux, oesophageal dysmotility and aspiration in chronic cough is controversial. Where previous guidance has supported an aggressive approach to acid suppression and pro-kinetic agents, the evidence base does not support their widespread use. High dose PPI may be trialled in patients with peptic symptoms, and/or evidence of reflux (either direct evidence at laryngoscopy, or an elevated Hull Airway Reflux Questionnaire score). Normal people score an average 4/70. The upper limit of normal is 13/70.

Bisphosphonates and calcium channel antagonists can worsen pre-existing reflux disease, and worsen cough.

Post-Nasal Drip/Upper Airways Cough Syndrome. The role of the nose in chronic cough remains controversial. A first-generation antihistamine, and decongestant can be trialled for 4 weeks. Intra-nasal steroids can be helpful in some cases.

Iatrogenic Cough. Chronic cough occurs in ~15% of patients taking ACE inhibitors. There is no temporal relationship between the start of ACE inhibitor treatment, and the development of cough. Any patient with a chronic cough should not receive ACE inhibitor treatment. ARB drugs do not affect the cough reflex and should be substituted in.

Chronic Refractory Cough. Cough which has not been responsive to trials of treatment for the above aetiologies, and persists. This form of cough may be responsive to neuro-modulatory treatment, such as opiates and pregabalin. Slow-release morphine 5-10 mg BD; Pregabalin up titrated to 75mg BD. These can be associated with side effects that limit their use, and benefit has only been demonstrated in small trials, and case series. Benefit should be assessed no later than 6 weeks after initiation of these therapies. Non-effective therapies should be weaned and stopped.

• Assessment focuses on ruling out respiratory illness and identifying possible triggers. 
• History with a focus on possible malignancy, infection, inhaled foreign body, ACE inhibitor usage, reflux symptoms, smoking history, and an alternative respiratory illness. Any evidence of ENT pathology?
• Clinical examination.

Investigations

• CXR
• Spirometry if asthma or COPD suspected
• HRCT is not required if the patient has a normal CXR and normal clinical examination.
• If there is clinical suspicion of an underlying respiratory illness (ILD, bronchiectasis) an HRCT can be requested from primary care.

Pharmacologic Management of Chronic Cough (>8 weeks)

• This guidance and the linked algorithm apply to the assessment and management of chronic cough symptom. The presence of additional symptoms or concerns (e.g. haemoptysis, weight loss, suspected cancer) should prompt further consideration as per the relevant associated referral pathway. 
• If clinical assessment or investigations detect an underlying respiratory illness, please refer to the specific respiratory sub-specialty via SCI-Gateway, as per clinical need. 
• Cough syncope
• Cough that interferes with occupation/profession – singers, teachers, drivers and is unresolved after following the steps outlined in the algorithm. (As selected patients may be eligible for onwards referral for specialist Speech and Language assessment).

• Patients with chronic cough symptom, but no other symptoms or signs to suggest an respiratory illness, and a normal Chest X-ray should be managed as per the treatment algorithm. 
• It is very common to not find a cause for a chronic cough; a chronic cough alone, present for 6 months or more is very unlikely to resolve.
• There are no other treatments available for isolated chronic cough symptom other than those in the algorithm and referral in this scenario will not add clinical benefit.
• A new or altered cough or additional symptoms should prompt re-assessment (from the start of the algorithm).

If investigations detect an underlying respiratory illness, please refer to the specific respiratory sub-specialty option on SCI-Gateway.

NHS Inform Cough
ERS Guidelines on the diagnosis and treatment of chronic cough in adults and children. 
Scottish Cancer Referral Guidelines (Lung)