[RS3PE: a clinical diagnosis, a prognosis more simple than its name].

Introduction: RS3PE syndrome (remittive symmetrical seronegative synovitis with pitting edema) was first described by MacCarthy in 1985. It is a rare type of seronegative polyarthritis occurring in the elderly.

Methods: Retrospective report of 13 cases (including eight male and five female patients; mean age 76.7 +/- 3.7 years) and search for previously reported cases, using the Medline database.

Results: Pitting edema was present at onset of disease in nine cases. Joint arthritis was bilateral, occurring in the wrist (13 cases), shoulder (six cases), elbow (six cases), knee (six cases), ankle (four cases), metacarpophalangeal (four cases) and hip (one case). Radiographies were normal. Mean erythrocyte sedimentation rate was 62 +/- 19 mm at the first hour and mean C-reactive protein level was 73 +/- 35 mg/L. Mild cholestasis was present in four of the seven patients for whom data were available. HLA B7 was present in five out of 12 cases (42%). Improvement was favorable, occurring over 7 months. Mean follow-up was 22.2 months. Fifty-nine other cases have been described in the literature. This syndrome, which affects the elderly, appears to be rare. Its clinical presentation is quite constant, with sudden onset, symmetrical polyarthritis and pitting edema. Its evolution, often long, is favorable. Rheumatoid arthritis and polymyalgia rheumatica are the main differential diagnoses.

Conclusion: Due to its favorable outcome and the usefulness of a mild corticotherapy, this syndrome, though rare, should be diagnosed where necessary in elderly patients.