Cutaneous lupus erythematosus (CLE) may have prognostic implications for systemic lupus erythematosus (SLE). We aimed to determine the impact of discoid lupus erythematosus (DLE) and malar rash on SLE disease activity.
Data were analyzed from the Toronto Lupus Clinic prospective cohort study. We compared SLE patients with active DLE or malar rash at SLE diagnosis to SLE patients who never developed CLE. Outcomes were assessed at one and five years, including Adjusted Mean Systemic Lupus Erythematosus Disease Activity Index 2000 (AMS).
A total of 524 SLE patients (284 without CLE, 65 with DLE, and 175 with malar rash) were included. Mean AMS scores in patients without CLE at one and five years were 5.96 ± 5.06 and 4.00 ± 3.52, which did not differ significantly from scores at one (6.93 ± 5.31, p = 0.17) and five years (4.29 ± 2.62, p = 0.63) in the DLE group. In patients with malar rash, AMS scores at one (8.30 ± 6.80, p < 0.001) and five years (5.23 ± 3.06, p = 0.004) were higher than controls without CLE.
Malar rash may be a marker of more severe systemic disease over time, while DLE has no significant impact on general SLE disease activity.