Causes of chronic cough in adults

postviral infection

cough following an acute viral respiratory tract infection such as acute rhinosinusitis or acute bronchitis; may last for more than 8 weeks

antibiotics have no role in treatment

pertussis

consider if cough lasts for more than 2 weeks

other features may be present (eg paroxysms of coughing, inspiratory whoop, post-tussive vomiting)

GORD

consider if patient has symptoms such as heartburn or regurgitation, night-time choking without symptoms of obstructive sleep apnoea, or if cough is worse at night or after eating specific foods

diagnosis often made clinically or following a response to empirical treatment with PPIs

chronic rhinosinusitis

other symptoms usually present (eg nasal blockage, obstruction or congestion, mucopurulent nasal discharge [with anterior or posterior drainage], facial pain or pressure, reduced sense of smell and taste, nausea)

coexisting allergic rhinitis may also present with symptoms such as sneezing, watery rhinorrhoea, nasal itching and itchy watery eyes

upper airway cough syndrome

(previously called postnasal drip)

may be associated with excessive mucus production (eg due to allergic or nonallergic rhinitis)

may be the result of an increased perception of normal volumes of postnasal mucus

inducible laryngeal obstruction

(also known as upper airway dysfunction or vocal cord dysfunction)

may be triggered by another cause of cough and worsened by irritants (eg gastro-oesophageal reflux, exposure to smoke or fumes, excessive use of the voice)

refer to a speech pathologist with expertise in inducible laryngeal obstruction for assessment and treatment

somatic cough syndrome or tic cough

(previously known as psychogenic or habit cough)

mostly occurs in children and adolescents

cough generally not present during sleep

obstructive sleep apnoea

nocturnal reflux or inflammation of the pharynx from snoring may contribute to cough

tuberculosis

can present with or without sputum, fever or weight loss

consider in patients who were born in or have visited countries where tuberculosis is endemic, or in patients with impaired immunity

lung or laryngeal cancer

consider in smokers older than 45 years with a new or altered cough, or cough with voice disturbance

urgently refer to a specialist

recurrent aspiration

risk of recurrent aspiration increased in Parkinson disease, stroke, dementia, COPD, impaired consciousness, or neuromuscular disorders affecting bulbar muscles

for definitions of aspiration-related terms and management of recurrent aspiration, see Aspiration pneumonia

asthma

uncontrolled asthma is a common cause of cough, but it is unusual for cough to be the sole symptom; other symptoms usually present (eg chest tightness, shortness of breath, wheeze, exercise limitation)

COPD or chronic bronchitis

productive cough, occurring every day for at least 3 months, at least 2 years in a row; more likely to present in heavy smokers of more than 20 pack years [NB4]

bronchiectasis

productive cough and recurrent chest infections

interstitial lung disease

dry cough, often associated with shortness of breath

cystic fibrosis

productive cough associated with gastrointestinal symptoms (eg frequent loose, oily bowel motions)

drug-induced cough

common precipitants include ACEIs and beta blockers

close relationship between starting a drug and development of cough is not always seen

review use of the precipitating drug