Background Systemic lupus erythematosus (SLE) occurs in 10% to 20% of cases before the age of 18. The aim of this study was to describe clinical, biological and immunological features of juvenile-onset SLE and to compare them to adult-onset SLE.

Patients and methods It is a retrospective study including 246 patients with SLE (ACR criteria). Patients were divided in two groups: juvenile-onset SLE (onset age <18 years) and adult-onset (age was between 18 and 50 years). Data were analysed and compared. P value was considered significant if <0.05.

Results Juvenile-onset SLE (jSLE) was diagnosed in 23 women and two men. Adult-onset disease (aSLE) was seen in 167 women and 12 men (no difference in sex-ratio).

Mean age at disease onset was 14.35±2.85 years in jSLE group and mean age at diagnosis was 16.25±4.38 years. Mean delay from SLE onset to diagnosis was 18 months in jSLE (similar to aSLE).

At disease onset, malar rash (88% vs 65.7%; p=0.025) and Raynaud’s phenomena (57.1% vs 34.3%; p=0.044) were significantly more frequent in young patients whereas lupus nephritis (36% vs 36.4%) and neurological involvements (12.5% vs 12.9%) were as frequent as in jSLE than in aSLE.

During follow up of patients with jSLE, frequencies of clinical manifestations were as follow: cutaneous manifestations (92%), lupus nephritis (56%), pericarditis (39%) and neurological involvements (25%) and had no statistical differences from aSLE.

Anaemia was noted in 82.6%, leucopenia in 52.2% of jSLE patients without statistical differences whereas thrombocytopenia was significantly more frequent (39.1% vs 20.6%; p=0.046).

Antinuclear antibodies, anti-DNA and anti-ENA were positive in 100%, 81% and 86.7% of jSLE respectively (no differences with aSLE). Anti-Sm antibodies were significantly more frequent in jSLE (92.3% vs 62%; p=0.033). Infections were diagnosed in 25% of jSLE (vs 25.9%).

Corticosteroids and immunosuppressive therapy prescription was comparable in both groups. Mortality rate was higher in jSLE (23.8% vs 9.4%.p=0.065).

Conclusion Mortality rate was higher in young SLE patients although severe manifestations and infections weren’t more frequent in this group