Refractory remitting seronegative symmetrical synovitis with pitting edema

Remitting seronegative symmetrical synovitis with pitting edema (RS3PE) is a rare rheumatic disease that can occur in elderly individuals and is characterized by symmetrical inflammatory arthritis and pitting edema. A 70-year-old male presented with joint pain and generalized body swelling for 2 months after an upper respiratory tract infection. RS3PE was clinically diagnosed after excluding other mimickers. The patient showed elevated platelet count and ferritin and C-reactive protein levels. The renal profile, hepatic profile, and thyroid function test results were unremarkable and were negative for hepatitis B and C, rheumatoid factor, anti-cyclic citrullinated peptide, and anti-Brucella antibodies. Echocardiogram findings confirmed normal cardiac function, thus excluding heart failure. Although RS3PE is commonly associated with neoplasm, computed tomography scans of the nasopharynx, chest, abdomen, and pelvis were unremarkable. Despite RS3PE being commonly associated with neoplasm, computed tomography of the nasopharynx, chest, abdomen, and pelvis were unremarkable. Treatment with oral prednisolone improved the symptoms but could not be tapered below 15 mg/day without relapse. Treatment with adalimumab was then started, which led to negative arthritis testing and resolution of distal extremity edema. RS3PE is a steroid-sensitive disease; however, biologics were required to control the disease in this case.