Clear (mucoid): COPD/bronchiectasis without current infection/rhinitis.
• Yellow (mucopurulent): acute lower respiratory tract infection/asthma.
• Green (purulent): current infection – acute disease or exacerbation of chronic disease, such as COPD.
• Red/brown (rusty): pneumococcal pneumonia (Fig. 5.3B). Try to distinguish between rusty and frank red blood (see below).
• Pink (serous/frothy): acute pulmonary oedema.
In bronchiectasis, the colour of sputum may be used to guide the need for antibiotic treatment