What are the key clinical features that suggest a diagnosis of interstitial lung disease in a primary care setting?

Key clinical features suggesting interstitial lung disease (ILD) in primary care include:

• Age over 45 years
• Persistent breathlessness on exertion
• Persistent cough
• Bilateral inspiratory crackles on chest auscultation
• Clubbing of the fingers
• Spirometry findings that are normal or show a restrictive pattern, though sometimes an obstructive pattern may be present

These features should prompt consideration of ILD and may warrant chest X-ray and referral to specialist care for further assessment and diagnosis.

References: These clinical features are based on NICE guidance for idiopathic pulmonary fibrosis, a common form of ILD, which is applicable in primary care assessment of suspected ILD NICE CG163.