Interesting Case of Adult Onset Stills Disease Presenting Without Rash

Summary: Introduction: Adult Onset Still's disease (AOSD) is a rare autoinflammatory disorder characterized by daily fevers, arthritis, and typical evanescent skin rash. It is a challenging diagnosis which should only be confirmed after excluding malignancies, infections, and some connective tissue diseases. Due to a lack of pathognomic clinical and laboratory features, the Yamaguchi criteria is used for the diagnosis. Classic skin rash is salmon-colored and tends to occur with fever and disappear during afebrile episode. Case presentation: We present the case of a young woman who presented with intermittent fever, severe polyarthralgia and joint swelling, myalgia, sore throat, leukocytosis, neutrophilia, thrombocytosis, anemia, elevated ferritin and inflammatory markers, axillary and pelvic lymphadenopathy and splenomegaly for 4 months. She had no typical salmon-colored evanescent skin rash, which made the diagnosis even more challenging. Patient had an extensive work up done, including bone marrow biopsy and lymph node core biopsy, which were unremarkable. She had extensive infectious work up done, which was also unrevealing. ANA/ENA, RF/CCP were negative. Conclusion: After we had ruled out infections, malignancy and other rheumatologic disorders, we concluded that the patient most likely had Adult-Onset Still’s disease. Patient’s symptoms responded well to high doses steroids. This is an interesting case because it shows that though characteristic rash is a part of the Yamaguchi Major diagnostic criteria, diagnosis of AOSD should not be overlooked after other differential diagnosis had been ruled out.