Adult-onset Still's disease (AOSD) is an inflammatory disorder of unknown aetiology characterized by a variety of clinical symptoms. AOSD can precede or occur concomitantly with AS and only a few cases of AOSD with AS have been reported. A 21-year-old man presented with spiking fever, sore throat, arthralgia, maculopapular rash, lymphadenopathy, and chronic inflammatory back pain. His laboratory findings showed marked elevations of liver enzyme, C-reactive protein, erythrocyte sedimentatioin rate, ferritin, and sacroiliitis (grade 2), which were the main characteristics of AOSD and AS. Most symptoms except chronic low back pain were improved after treatment with corticosteroid and disease modifying anti-rheumatic drugs. He was then treated with anti- tumor necrosis factor-alpha (anti-TNF-Ձ) agents to control the disease activity of AS and subsequently showed clinical and serological improvement. This is a first case report of AOSD combined with AS in Korea.

Keywords: Adult-onset Still's disease, Ankylosing spondylitis, Sacroiliitis, Crohn's disease