DESTIN, FLA. — Ethnicity appears to play an important role in the incidence and clinical manifestations of pediatric systemic lupus erythematosus, data from a recent study suggest.
Findings from the study of 87 white and 154 nonwhite children showed that more than 60% of age-matched controls without pediatric systemic lupus erythematosus (SLE) were white; however, fewer than 40% of the pediatric SLE patients were white. Black, Asian, and South Asian patients are overrepresented in the pediatric SLE population, Dr. Earl Silverman reported at a rheumatology conference sponsored by Virginia Commonwealth University, Richmond.
The study, which has been submitted for publication, found that mucocutaneous manifestations were more common in white children and organ involvement was more common in nonwhite children, said Dr. Silverman, professor of pediatrics and immunology at the University of Toronto.
Malar rash and photosensitivity were the mucocutaneous manifestations seen more often in the white patients, compared with the nonwhite patients (occurring in 86% vs. 66% and 40% vs. 18%, respectively). Renal disease occurred in 45% of the white patients, compared with 62% of the nonwhite patients, he noted. Central nervous system involvement occurred at similar rates in both groups (24% and 25%, respectively).
In regard to autoantibodies, ethnicity also appeared to play a role. Although anti-DNA, anticardiolipin, lupus anticoagulant, and anti-La antibodies were similar in white and nonwhite children, anti-Sm, anti-RNP, and anti-Ro were expressed more in the nonwhite patients (34% vs. 56%; 30% vs. 42%; and 28% vs. 45%, respectively).
The differences in course and incidence of SLE, based on ethnicity, are likely a result of interactions between genes and environment. Although there are no direct implications for physicians based on these findings, it is hoped that the study will help identify groups that are at low and high risk for mild and severe SLE, he said.
In addition to the ethnic differences in pediatric SLE, compared with adult SLE, physicians should also keep in mind that 20% of all SLE cases begin before age 18 years, with an overall prevalence of 10–20/10,000 children in this age group. In addition, girls are four times as likely as boys to develop SLE, Dr. Silverman said.
The diagnosis of pediatric SLE usually occurs during the ages of 11–14 years.
Common features are fever, weight loss, malaise or lethargy, and fatigue. Despite controversy over whether the features of SLE differ in pre- and postpubertal children, a study by Catherine DiSipio and her colleagues at Columbia University, New York, presented in poster form at the 2007 meeting of the American College of Rheumatology showed that the rates of arthritis, serositis, renal disease, central nervous system disease, and hematologic complications did not differ between the groups, nor did median SLE disease activity index.
However, intensive care unit admissions and deaths occurred more often in those younger than age 11 years, compared with those 11 years and older (32% vs. 21% and 11% vs. 0%, respectively).
Neuropsychiatric manifestations also can occur in pediatric SLE. Studies suggest that, among patients with neurologic involvement (about 25% of SLE patients), headache occurs in 68%, psychosis occurs in 36%, cognitive dysfunction occurs in 27%, cardiovascular disease occurs in 24%, seizures occur in 18%, mood disorders occur in 15%, and chorea occurs in 11%.
Visual hallucinations are a hallmark of SLE-related psychosis in pediatric patients. Visual distortions are often seen, as is sensitivity to light and sound. Magnetic resonance imaging is frequently normal in SLE-related psychosis, but a SPECT scan can be helpful for differentiating it from idiopathic schizophrenia, he said.