Objectives: To assess trends in the cutaneous variants of lupus erythematosus (CLE) and to ascertain the incidence of CLE over the past 4 decades.
Design: Retrospective population-based study.
Setting: Community-based epidemiology project.
Patients: All Olmsted County, Minnesota, residents with any subtype of CLE between January 1965 and December 2005.
Main outcome measures: Incidence of CLE and disease progression to systemic LE (SLE).
Results: A total of 156 patients with newly diagnosed CLE (100 females and 56 males) were identified between 1965 and 2005. The incidence rate (age and sex adjusted to the 2000 US white population) was 4.30 (95% confidence interval [CI], 3.62-4.98) per 100,000. The age- and sex-adjusted prevalence as of January 1, 2006, was 73.24 (95% CI, 58.29-88.19) per 100,000. Nineteen patients with CLE had disease progression to SLE: cumulative incidence at 20 years, 19%; mean (SD) length to progression, 8.2 (6.3) years. Compared with a previously reported incidence of 2.78 (95% CI, 2.08-3.49) per 100,000 for SLE among Rochester, Minnesota, residents in 1965 through 1992, the incidence of CLE in Rochester was 3.08 (95% CI, 2.32-3.83) per 100,000 in 1965 through 1992.
Conclusions: The incidence of CLE is comparable to the published incidence of SLE. Our findings double the incidence of the root designation of the disease process known as LE (SLE and CLE).