Elderly Patients With Inflammatory Polyarthritis: The Importance of Including Remitting Seronegative Symmetrical Synovitis With Pitting Edema (RS3PE) in the Differential Diagnosis.

Remitting symmetrical seronegative synovitis with pitting edema (RS3PE) is a rare seronegative inflammatory arthritis that primarily affects older adults. Clinical features include acute onset, symmetric polyarthritis in the upper extremities, pitting edema in the dorsum of the hands, age of onset > 60 years, and rapid response to medium-dose steroids. Rheumatoid factor and joint erosions are typically absent. Despite its favorable prognosis, RS3PE is frequently misdiagnosed in older adults due to overlapping comorbidities, posing diagnostic challenges. We present a case of a 92-year-old male with recurrent RS3PE who initially presented with acute symmetric upper extremity edema, polyarthritis, and a dramatic response to prednisone. His symptoms recurred three years after remission, which is unusual. As the population ages and life expectancy increases, it is likely clinicians will see an increase in the incidence of RS3PE. Understanding the clinical nuances and subtleties in distinguishing this condition from other inflammatory and crystalline arthropathies will lead to improved diagnostic accuracy and management. Furthermore, the high association of RS3PE with concurrent malignancy warrants age-appropriate cancer screening and a careful balance of diagnostic investigation and goals of care in those with advanced age. Exploration of "what matters most," one of the pillars of age-friendly care, should guide clinicians on how best to proceed.