See Differential Diagnosis for more details
Chronic cough as a sole symptom typically lasts for months or years before presentation and does not usually represent an urgent medical condition. A faster and more comprehensive evaluation (rather than empirical treatment) should take place if other symptoms are present (such as dyspnoea, haemoptysis, weight loss, fever, or chest pain) or if the patient has concurrent depression of the local, humoral, or cellular components of the immune system due to neutropenia, acquired immunodeficiency syndrome, or use of glucocorticoids, chemotherapy, or anti-rejection medications.
Cough is the most common symptom of lung cancer. Lung cancer enters the differential diagnosis especially if cough is accompanied by weight loss, haemoptysis, chest pain, dyspnoea, or hoarseness and is more likely in current or prior smokers. Diagnosis is confirmed by radiography and pathology, and treatment may involve surgery, chemotherapy, and radiotherapy.
Chronic cough accompanied by episodic dyspnoea and wheezing that worsens at night, on exposure to allergens, cold, or fumes, may indicate asthma. Diagnosis is based on the above symptoms, clinical findings of bronchoconstriction, with obstructive pattern of pulmonary function tests. Treatment relies on use of bronchodilators and anti-inflammatory agents.
May follow a prodrome of chronic cough and, in that instance, is typically manifested with a change in the character of cough, appearance of sputum purulence, and fever. Less commonly, haemoptysis, chest pain, or dyspnoea may be present. Diagnosis is based on clinical findings of lung consolidation, along with radiographic findings of an infiltrate. Treatment consists of antibiotics.
Chronic cough accompanied by night sweats and weight loss may indicate tuberculosis, especially in a patient living in or visiting an area with high prevalence of this disease. Tuberculosis is typically accompanied by radiographic infiltrative, fibrotic, or cavernating changes and confirmed by demonstration of Mycobacterium tuberculosis bacilli in sputum.
Bordetella pertussis infection
Paroxysmal cough, inspiratory whooping, and post-tussive vomiting raise a possibility of B pertussis infection. Diagnosis is suspected in household contacts of whooping cough and confirmed with microbiological or serological testing. B pertussis infection is treated with beta-lactam, fluoroquinolone, or macrolide antibiotics.
Interstitial pulmonary fibrosis
Cough accompanied by progressive dyspnoea may indicate the presence of interstitial pulmonary fibrosis. Diagnosis is further suspected with signs of dry crackles and clubbing and confirmed clinically or pathologically. Radiography shows a plethora of interstitial changes, and pulmonary function testing typically demonstrates a restrictive pattern. Treatment depends on the specific clinical and pathological pattern of disease.