Background The diagnosis of systemic lupus erythematosus (SLE) in children is challenging as the heterogeneous manifestations and disease impact on the child's growth highlighted the importance of timely diagnosis and management.

Objectives The aim of the present study was to assess and compare the clinical characteristics, disease activity and damage between juvenile (JSLE) and juvenile-onset (JO-SLE) Egyptian patients.

Methods Seventy-eight SLE patients (26 JSLE and 52 JO-SLE) were included in this study. Disease activity was assessed using the SLE Disease Activity Index (SLEDAI) and organ damage using the Systemic Lupus International Collaborating Clinics (SLICC) index.

Results The mean age of the JSLE children was 13.25±2.09 years and 23.17±4.26 years for JO-SLE cases. JO-SLE cases were older at disease onset with a higher female-to-male ratio. There were no noticeable gender differences. There was a significantly higher frequency of serositis, nephritis and hematological involvement in the JO-SLE (57.7%, 76.9% and 73.1%) compared to the JSLE cases (15.4%; 30.8% and 30.8%) (p<0.001 for all). The erythrocyte sedimentation rate, creatinine and proteinuria were significantly increased in JO-SLE while alkaline phosphatase was higher in JSLE cases. In JO-SLE cases, SLEDAI significantly increased (5.96±6.18 vs 3.12±1.97; p=0.003) and the SLICC tended to increase compared to the JSLE children. More JO-SLE cases received hydroxychloroquine and azathioprine.

Conclusions The existence of differences in clinical phenotype has been confirmed, between JSLE and JO-SLE especially as regards serositis, nephritis and heamatological affection. The disease damage was comparable which denotes that the maximum organ involvement occurs in childhood with an almost stationary course. Rheumatologists caring for children with SLE must be aware of the greater risk of major haematological and renal involvement as well as important long-term morbidity.

Disclosure of Interest None declared