Adult-onset Still's disease-associated interstitial lung disease represents severe phenotype of the disease with higher rate of haemophagocytic syndrome and relapse.

OBJECTIVES: Adult-onset Still's disease (AOSD) is an inflammatory disorder characterised by sustained fevers, arthritis, and skin involvement. Interstitial lung disease (ILD) is a rare manifestation, and its clinical characteristics have yet to be determined.

METHODS: We sought to examine the clinical characteristics of AOSD-associated ILD. We retrospectively investigated 78 patients diagnosed as AOSD. ILD was diagnosed based on chest high-resolution computed tomography (HRCT). Clinical characteristics were compared between patients with and without ILD. Relapse was defined as sustained fevers, re-emergence of arthritis, and skin involvement after remission. We further investigated the pathological features of ILD on available samples.

RESULTS: Patients with ILD, found in 9 of 78 (11.5 %), had older age of onset (mean age 62.6) than those without ILD (mean age 38.8) (p<0.01). The 3-year survival rates were comparable between patients with ILD (92.5%) and those without ILD (88.9%) (p=0.23). Patients with ILD had a higher cumulative rate of haemophagocytic syndrome (HPS) and relapse than those without (p<0.0001 and p=0.009, respectively). Chest HRCT showed marked thickening of the interlobular septa, the bronchovascular bundles, or the visceral pleura in all cases. There was no honeycomb or volume loss. Pulmonary pathological findings revealed marked thickening of the visceral pleura and the interlobular septa.

CONCLUSIONS: Patients with ILD might have higher risks for HPS and relapse. Careful observation and appropriate therapeutic intervention might be needed.