Clinical classification criteria proposed for discoid lupus erythematosus

Atrophic scarring and location in the conchal bowl are two of six clinical classification criteria that may be applied to discoid lupus erythematosus, according to results of an effort to create standardized criteria for this disease.

“No universally recognized classification criteria currently exist for discoid lupus erythematosus (DLE), which has led to problematic heterogeneity in observational and interventional clinical studies across the field,” Scott A. Elman, MD, of the department of dermatology at Brigham and Women’s Hospital, Harvard Medical School, Boston, and colleagues wrote.

In the current diagnostic study, they prospectively applied 12 previously defined candidate criteria items for DLE used by dermatologists and dermatopathologists.

Those criteria included erythematous to violaceous in color; atrophic scarring; dyspigmentation; follicular hyperkeratosis/plugging; scarring alopecia; location in the conchal bowl; preference for head and neck; interface/vacuolar dermatitis; perivascular and/or periappendageal lymphohistiocytic infiltrate; follicular keratin plugs; mucin deposition; and basement membrane thickening.

Patients with suspected DLE or a DLE mimicker who were seen at nine dermatology practices in the United States, Japan, Poland and South Korea from Dec. 1, 2017, to Feb. 1, 2019, underwent analysis. While the final analysis included 215 patients, the researchers noted that 15 of these patients had missing or incomplete data.

Results for the final model indicated that six of the 12 criteria may be applied for DLE classification. Atrophic scarring topped the list with three points after undergoing logistic regression analysis, improvement tests, fit statistics and discrimination. Location in the conchal bowl and preference for the head and neck were next with two points each, followed by dyspigmentation, follicular hyperkeratosis/plugging and erythematous to violaceous color at one point each.

Further analysis showed that these characteristics had an area under the receiving operating characteristic curve of 0.91 (95% CI, 0.87-0.95).

To calculate the effectiveness of this system, the researchers noted that a score of at least five points carried a sensitivity of 84.1% and a specificity of 75.9% in the classification of DLE. As scores increase, specificity increases accordingly.

The researchers noted that many of the features used in the classification criteria represent disease damage as opposed to DLE disease activity. “Overall, the importance of DLE classification is highlighted by the need to ensure that patients categorized as having DLE for inclusion in studies do indeed have the disease based on defined characteristics,” they wrote. “We hope that classification criteria will provide investigators with a foundation on which to base observational and interventional clinical trials and a common language with which to communicate effectively about this population.”