Still's Disease Onset in Older Adults: Clinical Features, Diagnosis, and Management.

Still's disease (SD) is a rare systemic inflammatory disease that is characterized by high fever, polyarthritis, and an evanescent rash as its main symptoms but that may also be complicated by pleuritis and macrophage activation syndrome (MAS). There has been a recent increase in studies on older-onset SD, which presents with less-typical clinical features, such as sore throat, skin lesions, and splenomegaly, but more complications including pleuritis and disseminated intravascular coagulation. Several reports have shown higher levels of inflammatory markers, including serum ferritin, and poorer outcomes in terms of survival and drug-free remission in older patients. In addition, caution is needed when diagnosing SD in older patients because of the increased incidence of differential diagnoses such as infectious diseases, malignancies, and inflammatory diseases. Prognosis is poor in older patients, and treatment-associated infections and severe complications such as MAS are the main cause of mortality. The use of biologics and treatment response may not differ greatly between older and younger patients. Although the data are limited, anti-IL-1 and anti-IL-6 agents may control SD in these patients with careful use and adequate infection prevention. Recent studies that classified adult-onset SD by cluster analysis or latent class analysis showed that older patients form a unique cluster of SD, indicating the need for clinicians to pay more attention to the diagnosis and management of SD in older patients.