Classifying discoid lupus erythematosus: background, gaps, and difficulties

Clinical aspects of cutaneous lupus erythematosus

Lupus erythematosus (LE) is an autoimmune inflammatory disease with a wide clinical spectrum from life-threatening multi-organ inflammation in systemic lupus erythematosus (SLE) to limited skin disease in cutaneous LE (CLE). The etiology of CLE is still not fully understood but a multifactorial genesis with genetic predisposition and certain environmental factors as triggers for the development are generally accepted features. Lesions can be induced and aggravated by UV-irradiation and smoking is linked to more severe forms of skin disease and to co-morbidity. Drugs, including many common medicines like antihypertensives, are known to induce subacute CLE (SCLE). The mechanisms involved have recently been shown to be part of the IFN-I pathway and new, specific treatments are currently in clinical trials. CLE is currently classified in subtypes based on clinical presentation and duration into acute CLE (ACLE), SCLE, and chronic CLE (CCLE). Distinct subtypes can be seen in individual patients or coexist within the same patient. Because of the confluent and overlapping picture between these subsets, serology, and histopathology constitute an important role guiding towards correct diagnose and there is ongoing work to update the classification. The Cutaneous Lupus Area Severity Index (CLASI) is a validated tool to measure activity and damage both in clinical trials but also for the clinician to evaluate treatment and follow the course of the disease among patients. CLE is known to have substantial impact on the life of those affected. Several tools have been proposed to measure QoL in these patients, currently Skindex-29 is probably the most used. Patient education is an important part of prevention of flares, including UV-protection and smoking cessation. First-line treatment includes topical corticosteroids as well as topical calcineurin inhibitors with the addition of systemic treatment with antimalarials in more severe or therapy resistant cases. Treatment specifically targeting CLE has been lacking, however novel potential therapies are in later phase clinical trials. In this review we aim to describe the different subsets of the cutaneous form in LE with focus on clinical aspects.

Implications of dermoscopy and histopathological correlation in discoid lupus erythematosus in skin of color

Background:

Discoid lupus erythematosus (DLE) is chronic dermatosis manifests as scaly indurated plaques with erythema and peripheral hyperpigmentation. Few cases progress to systemic lupus erythematosus. Differentials include lichenoid photo dermatitis, Jessner's lymphocytic infilterate, and polymorphus light eruptions. It is difficult to assess the activity clinically. Histopathology is characteristic and evaluation of disease activity is possible. Dermoscopy is a useful diagnostic method in many dermatoses. Dermoscopy is reflection of histological changes. Hence, dermoscopic features may act as a tool for activity assessment. Here authors have pursued dermoscopic and histopathological correlation in DLE lesions to assess the activity of disease.

Aims:

To study dermoscopic features in DLE and correlate the patterns with histopathological changes in skin of color.

Method:

This study was conducted in a tertiary hospital. Clinically suspected and histopathologically proven lesions of DLE were enrolled in this study. The target lesion was marked and sent for biopsy after performing dermoscopy. Activity of the lesion was assessed on the basis of histopathological features. SPSS statistics for windows v20.0 (SPSS Inc, Chicago, USA) was used to analyze data. Chi-square and Fisher's χ² test was used to statistically signify association. Cohen's kappa coefficient was used to determine the agreement.

Results:

Study included 110 patients with Fitzpatrick skin type IV-V having 120 lesions. Follicular keratotic plug [73 (60.8%)] and peri-follicular whitish halo [65(54.1%)] were commonly found in dermoscopy. Blue-gray and brown dots, telangiectasia, follicular red dots, white rosettes and white areas include other features. Interface dermatitis, peri-appendageal infilterate, melanin incontinence, melanophages and fibrosis were noted in histopathology. Perfect agreement was observed in follicular plugs.

Conclusion:

Dermoscopy patterns were well correlated with histopathological changes. Thus dermoscopy played an important role in assessing the activity of lesion.

Creation and Validation of Classification Criteria for Discoid Lupus Erythematosus

Importance

Classification criteria are the standardized definitions that are used to enroll uniform cohorts for research studies. They emphasize high specificity and are distinct from diagnostic criteria. 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.

Objective

To create and validate classification criteria for DLE using 12 previously defined candidate criteria items.

Design, Setting, and Participants

For this diagnostic study, candidate criteria items were prospectively applied by dermatologists and dermatopathologists at clinical visits of patients with DLE or a condition that could be confused for DLE, termed a DLE mimicker, at academic dermatology practices across the United States, Poland, Japan, and South Korea. Data were collected from December 1, 2017, to February 1, 2019, and analyzed from March 1 to September 19, 2019.

Main Outcomes and Measures

Clinical features among these 2 groups were calculated and compared with χ2 or Fisher exact tests. Candidate models were identified using best subsets logistic regression analysis. Improvement tests, fit statistics, and discrimination were considered to choose a final model.

Results

Nine sites contributed 215 patients, 15 of whom had missing or incomplete data. The final model for DLE classification criteria includes only clinical variables: atrophic scarring (3 points), location in the conchal bowl (2 points), preference for the head and neck (2 points), dyspigmentation (1 point), follicular hyperkeratosis and/or plugging (1 point), and erythematous to violaceous in color (1 point), with an area under the receiving operating characteristic curve of 0.91 (95% CI, 0.87-0.95). A score of at least 5 points yields a sensitivity of 84.1% and a specificity of 75.9% in the classification of DLE, with increasing scores yielding higher specificity.

Conclusions and Relevance

These findings provide the initial validation of classification criteria for DLE for use in observational and clinical trials.

A novel TRAF3IP2 variant causing familial scarring alopecia with mixed features of discoid lupus erythematosus and folliculitis decalvans

Discoid lupus erythematosus (DLE) is an autoimmune disorder with a poorly defined etiology. Despite epidemiologic gender and ethnic biases, a clear genetic basis for DLE remains elusive. In this study, we used exome and RNA sequencing technologies to characterize a consanguineous Lebanese family with four affected individuals who presented with classical scalp DLE and generalized folliculitis. Our results unraveled a novel biallelic variant c.1313C > A leading to a missense substitution p.(Thr438Asn) in TRAF3IP2(NM_147200.3). Expression studies in cultured cells revealed mis-localization of the mutated protein. Functional characterization of the mutated protein showed significant reduction in the physical interaction with the interleukin 17-A receptor (IL17RA), while interaction with TRAF6 was unaffected. By conducting a differential genome-wide transcriptomics analysis between affected and non-affected individuals, we showed that the hair follicle differentiation pathway is drastically suppressed, whereas cytokine and inflammation responses are significantly upregulated. Furthermore, our results were highly concordant with molecular signatures in patients with DLE from a public dataset. In conclusion, this is the first report on a new putative role for TRAF3IP2 in the etiology of DLE. The identified molecular features associated with this gene could pave the way for better DLE-targeted treatment.

Alopecias in lupus erythematosus

Several patterns of hair loss can occur in lupus erythematosus (LE). Alopecias which show histological characteristics of LE are LE-specific, and include discoid LE (DLE), diffuse or patchy hair loss in acute LE, subacute cutaneous LE, and rarely tumid LE. Lupus hair in SLE is a poorly characterised entity and may be a form of telogen effluvium. Alopecia areata can coexist with LE and may mimic DLE. Non-lupus alopecias such as telogen effluvium and anagen effluvium have a myriad of causes which include disease flares, drugs and stress in the setting of LE. The latest validated Systemic Lupus International Collaborating Clinics classification criteria for SLE includes non-scarring alopecia as a criterion; therefore, recognising the aetiology of hair loss in the setting of LE is crucial in classifying a patient to have systemic disease.