Fever acquired overseas is not always infectious in etiology: adult-onset Still's disease in a soldier deployed to Afghanistan.

Adult-onset Still's disease (AOSD) is a rare systemic inflammatory disorder of unknown etiology characterized by spiking fever, arthritis or arthralgia, rash, and leukocytosis. The nonspecific findings and epidemiology of the disease can complicate the diagnosis among deployed U.S. personnel, because they are exposed to infectious etiologies that can present in a similar fashion. We present a case of 19-year-old U.S. Army soldier who was deployed to Afghanistan and eventually medevaced to Walter Reed National Military Medical Center complaining of arthralgia, diffuse myalgia, daily spiking fever, and laboratory abnormalities including leukocytosis and elevated liver-associated enzymes. After an initial concern for an infectious etiology, the patient met Yamaguchi criteria for the diagnosis for AOSD. The patient's clinical course, pertinent laboratory, and pathology data are reviewed in the context of approaching the diagnosis and treatment of AOSD. This case highlights that providers need to maintain a high clinical suspicion for less common conditions such as AOSD in the setting of unresolving nonspecific findings such as fever, rash, and leukocytosis.