RESUMO
@#BACKGROUND: Adult-Onset Still's Disease is a rare inflammatory disorder with an estimated incidence of 1 in 1,000,000 that presents with a rash, fever, and arthritis. Furthermore, there have only been three reported cases in the Philippines. Its presentation is similar to other more commonly encountered inflammatory disorders; however, it is the negative immunologic and serologic workup that typically distinguishes this rare specific inflammatory disorder along with the fulfillment of diagnostic criteria set by Yamaguchi and Cush. CASE: This is a case of an 18-year-old female who presented with recurrent fever, rash, and polyarthritis. The patient underwent extensive workup, but immunologic studies were negative. A consideration of Adult-Onset Stills Disease was made and along with the fulfillment of the classification criteria set by Yamaguchi and Cush, the diagnosis was clinched and the patient was started on glucocorticoid therapy where improvement of the patient's condition was noted with the resolution of the fever, rash and minimal complaints of joint pain. CONCLUSION: Adult-Onset Still’s Disease is an uncommon inflammatory disorder that confers high morbidity and disability. It commonly presents with shared clinical features among other inflammatory disorders; thus, recognition of the existence of this disease entity could pose a diagnostic dilemma. A high clinical suspicion along with negative studies and fulfillment of the diagnostic criteria avoids unnecessary workup and inappropriate management.