Clinical analysis of rash in systemic lupus erythematosus

Abstract

Objective To investigate the clinical significance of rash in patients with systemic lupus erythematosus (SLE). Methods Six hundred and sixty-one SLE patients were enrolled into the study. The patients were divided into either a rash group or a control group (without rash manifestations) to compare the clinical findings, laboratory findings, and disease activity. The chi-square test was used to compare the number of clinical manifestations and the number of abnormal laboratory results in the two groups. The t-test was used to compare serum complement C3 and C4 levels and SLEDAI score between the two groups. Logistic regression was used to analyze the relation of rash with sex, onset age, clinical manifestations, and laboratory results. Results Among the 661 SLE patients, 338 (51.1%) had rash manifestations. The incidence of fever (38.5%), oral ulcer (27.8%), hair loss (39.3%), and arthritis (63.0%) in the rash group was significantly higher than that in the control group (38.5% vs 30.3%, χ2=4.821, P=0.028; 27.8% vs 19.2%, χ2=6.800, P=0.009; 39.3% vs 25.1%, χ2=15.366, P<0.001; and 63.0% vs 51.4%, χ2=9.124, P=0.003, respectively). The incidence of anemia in the rash group was lower than that in the control group (56.8% vs 64.4%, χ2=3.984, P=0.046). Immunological findings showed that the level of complement C3 was lower in the rash group than in the control group [(0.47±0.27) vs (0.55±0.27), χ2=-3.929, P<0.001]. SLE patients with rash had higher prevalence of anti-dsDNA antibody and anti-Sm antibody than those in the control group (84.3% vs 77.7%, χ2=4.707, P=0.030; and 41.7% vs 27.9%, χ2=13.941, P<0.001, respectively). The logistic regression analysis showed that oral ulcer (OR=3.523, P<0.001), hair loss (OR=4.549, P<0.001) and arthritis (OR=1.758, P=0.002) were risk factors for SLE rash, while older age (OR=0.502, P=0.006), no anemia (OR=0.613, P=0.012), and normal complement C3 level (OR=0.472, P=0.006) were protective factors. Conclusion Rash is one of the most common clinical manifestations of SLE and may be a marker of more severe systemic disease over time in SLE patients. Rash in SLE patients is closely related to age of onset, clinical manifestations, and serological abnormalities. Key words: Systemic lupus erythematosus; Rash; Clinical manifestations