Managing RS3PE: Diagnostic approach, initial steroid response, and long-term management with DMARDs

Background. RS3PE, or Remitting Seronegative Symmetrical Synovitis with Pitting Edema, is a unique and relatively rare form of inflammatory arthritis that predominantly affects older adults. It is distinguished by its hallmark features: symmetrical swelling of the joints, significant pitting edema in the extremities, and a negative serological profile for common markers associated with rheumatoid arthritis, such as rheumatoid factor (RA factor) and anti-citrullinated protein antibodies (anti-CCP). This condition is often characterized by a remitting course, meaning that symptoms may improve or resolve over time, particularly with appropriate treatment. The condition usually affects older adults and can sometimes be associated with other underlying health issues, such as malignancies or infections. The “remitting” aspect of RS3PE refers to the fact that the symptoms often improve or resolve over time, particularly with appropriate treatment, which usually involves corticosteroids or other anti-inflammatory medications. Case report. This case study details the clinical presentation, diagnosis, and management of a 56-year-old female patient with known hypertension who presented with bilateral dorsal hand swelling, pain, and early morning stiffness over a 15-day period. The patient’s initial examination revealed bilateral pitting edema and active arthritis in the proximal interphalangeal joints, with significant warmth and tenderness. Laboratory tests showed elevated ESR and CRP, normocytic normochromic anemia, and negative rheumatoid factor and anti-CCP antibodies. Imaging studies, including X-ray, ultrasound, and mammogram, showed no erosive changes or malignancy, while a Pap smear and serum CA-125 levels were within normal limits. The clinical picture, combined with the exclusion of other conditions, supported the diagnosis of RS3PE. Treatment commenced with intravenous low-dose dexamethasone, which led to significant symptomatic improvement. This was followed by a transition to oral prednisolone, and the patient initially showed complete resolution of symptoms. However, recurrence of symptoms occurred upon discharge, prompting the introduction of steroid-sparing agents: methotrexate and hydroxychloroquine, alongside continued oral steroid treatment. Over a two-month follow-up period, the patient experienced no signs of relapse. This case fits the clinical and investigative criteria for RS3PE. The patient showed symptomatic improvement after treatment with low-dose steroids.