Desquamative interstitial pneumonia: an analytic review with an emphasis on aetiology.

Desquamative interstitial pneumonia (DIP) is characterised by the accumulation of numerous pigmented macrophages within most of the distal airspace of the lung and, sometimes, the presence of giant cells. Diagnosis of DIP is not easy and requires surgical lung biopsy. DIP is usually associated with tobacco smoke. However, the association between smoking and DIP is less robust than that with respiratory bronchiolitis with interstitial lung disease or pulmonary Langerhans' cell histiocytosis; approximately 10-42% of patients with DIP are nonsmokers. DIP can also occur in patients following exposure to certain inhaled toxins (occupational exposure) and drugs, and may occur in the context of certain viral illnesses and autoimmune diseases. In the context of DIP, occupational exposure should be systematically investigated.