Background and Aims To evaluate prevalence, clinical manifestations, laboratory abnormalities, treatment and outcome in a multicenter cohort of childhood-onset systemic lupus erythematosus(cSLE) patients with and without panniculitis.

Methods Panniculitis was diagnosed due to painful subcutaneous nodules and/or plaques in deep dermis/subcutaneous tissues and lobular/mixed panniculitis with lymphocytic lobular inflammatory infiltrate in skin biopsy. Statistical analysis was performed using Bonferroni correction(p<0.004).

Results Panniculitis was observed in 6/847 (0.7%) cSLE. Painful subcutaneous erythematosus and indurated nodules were observed in 6/6 panniculitis patients and painful subcutaneous plaques in 4/6. Generalised distribution was evidenced in 3/6 and localised in upper limbs in 2/6 and face in 1/6. Histopathology features showed lobular panniculitis without vasculitis in 5/6(one of them had concomitant obliterative vasculopathy due to antiphospholipid syndrome) and panniculitis with vasculitis in 1/6. Comparison between cSLE with panniculitis and 60 cSLE without panniculitis with same disease duration [2.75 (0–11.4) vs. 2.83 (0–11.8) years, p=0.297], showed higher frequencies of constitutional involvement (67% vs. 10%,p=0.003), leukopenia (67% vs. 7%, p=0.002) and median C-reactive protein (10.5 vs. 0.5 mg/L, p=0.001). Cutaneous atrophy and hyperpigmentation occurred in 83% of patients.

Conclusions Panniculitis is a rare skin manifestation of cSLE occurring in the first three years of disease with considerable sequelae. The majority of patients have concomitant mild lupus manifestations.