ACUTE SARCOID ARTHRITIS - OCCURRENCE, SEASONAL ONSET, CLINICAL-FEATURES AND OUTCOME

In a 2-yr prospective follow-up study of patients presenting clinicall y with possible reactive arthritis (ReA), 17 (9%) of the patients turn ed out to have acute sarcoid arthritis (SA). The number of new cases o f SA per year was 2.9/100 000 persons in the city of Oslo between 18 a nd 60 yr of age. The onset of SA clustered in the spring. All the SA p atients presented with bilateral ankle joint involvement and bilateral hilar lymphadenopathy, and ten (59%) presented with the triad of eryt hema nodosum, arthritis and lung involvement. A prospective follow-up after 104 weeks showed complete remission of arthritis in all 17 cases of SA. The total duration of arthritis [median (range)] was 11 (2-107 ) weeks. Erythema nodosum was mild and transient in all cases. At week 104, the lung and hilar manifestations had resolved. We conclude that the outcome of SA appeared favourable. Bilateral ankle joint involvem ent, erythema nodosum and bilateral hilar lymphadenopathy found at the routing chest X-ray examination are important clues for the diagnosis of SA.