eng Science and Education Publishing American Journal of Medical Case Reports 2374-216X 2023-12-19 11 12 172 175 10.12691/ajmcr-11-12-2 AJMCR202311122 article Su Hyun Jeong suhyunj@unr.edu 1 Nishitha Shekhar 1 Matthew Amin 1 Amir Nabizadeh 2 Neelesh Mutyala 3 University of Nevada Reno, Department of Internal Medicine, Reno, NV University of Minnesota, Department of Internal Medicine, Minneapolis, MN University of Texas Health Science Center at Houston, Department of Internal Medicine, Houston, TX We report a case of Adult-onset Still¡¯s Disease (AoSD) in a 55-year-old male without prior rheumatological history. The disease is an autoinflammatory condition with features including fevers, joint pain, and salmon-colored lesions. Diagnosis is through clinical classification systems including the Yamaguchi or Fautrel criteria and considered after a thorough diagnosis of exclusion. However, the disease is rare and difficult to recognize given its nonspecific presentation. This patient depicts the challenges in noticing the disease, especially in the setting of confounding physical exam findings. Prognosis is favorable, but prolonged periods without treatment can lead to the development of harmful complications including fulminant hepatitis, lymphohistiocytic activation syndrome, and disseminated intravascular coagulation. https://pubs.sciepub.com/ajmcr/11/12/2/ajmcr-11-12-2.pdf adult-onset still's disease yamaguchi criteria fautrel criteria systemic juvenile idiopathic arthritis