Early psoriatic arthritis: The clinical spectrum

Objective. The aim of this study was to characterize the clinical pattern of early psoriatic arthritis (EPA). Methods. We studied 47 consecutive patients: 29 patients had definite psoriatic arthritis and 18 had the "sine psoriasis" subset. Inclusion criteria were an articular and/or an entheseal involvement lasting no more than 12 weeks and the exclusive use, before enrollment, of non-steroid anti-inflammatory drugs to control articular symptoms. All patients underwent clinical examination, blood tests, total body bone scintigraphy, articular ultrasonography and radiography of joints and/or entheses clinically involved. Results. On the basis of clinical examination, EPA was an oligo-enthesoarthritis in over 75% of the patients studied. In contrast, the number of joints and/or entheses showing increased tracer uptake at bone scintigraphy was 3 times greater as compared to clinical evidence (p < 0.001). Articular ultrasonography confirmed the inflammatory involvement of synovium and/or entheses in all articular sites active at bone scintigraphy, but silent at clinical examination. In addition, 7 patients showed the occurrence of joint and/or entheseal erosions at standard radiography. Conclusion. The results of this study demonstrate that bone scintigraphy yields a more accurate evaluation of entheso-articular involvement and distribution in patients with EPA. In addition, our results suggest that clinical oligo-enthesoarthritic presentation of EPA might represent in most cases a polyarticular condition, which is at an increased risk of clinical progression. These findings have a significant impact on the clinical decision making process in EPA patients.