Cutaneous lupus erythematosus: a review of etiopathogenic, clinical, diagnostic and therapeutic aspects

The Spectrum of Cutaneous Manifestations in Lupus Erythematosus: A Comprehensive Review

Lupus erythematosus (LE) is an autoimmune inflammatory disease with complex etiology. LE may present as a systemic disorder affecting multiple organs or be limited solely to the skin. Cutaneous LE (CLE) manifests with a wide range of skin lesions divided into acute, subacute and chronic subtypes. Despite classic forms of CLE, such as malar rash or discoid LE, little-known variants may occur, for instance hypertrophic LE, chilblain LE and lupus panniculitis. There are also numerous non-specific manifestations including vascular abnormalities, alopecia, pigmentation and nail abnormalities or rheumatoid nodules. Particular cutaneous manifestations correlate with disease activity and thus have great diagnostic value. However, diversity of the clinical picture and resemblance to certain entities delay making an accurate diagnosis The aim of this review is to discuss the variety of cutaneous manifestations and indicate the clinical features of particular CLE types which facilitate differential diagnosis with other dermatoses. Although in diagnostically difficult cases histopathological examination plays a key role in the differential diagnosis of LE, quick and accurate diagnosis ensures adequate therapy implementation and high quality of life for patients. Cooperation between physicians of various specialties is therefore crucial in the management of patients with uncommon and photosensitive skin lesions.

Tumid Lupus Erythematosus (TLE): A Review of a Rare Variant of Chronic Cutaneous Lupus Erythematosus (cCLE) with Emphasis on Differential Diagnosis

Tumid lupus erythematosus (TLE) has been the subject of heated debate regarding its correct nosographic classification. The definition of TLE has changed over time, varying according to the different studies performed. In this review, we address the initial definition of TLE, the changes that have taken place in the understanding of TLE, and its placement within the classification of cutaneous lupus erythematosus (CLE), with a focus on clinical, histopathological, immunophenotypical, and differential diagnosis aspects.

Dermoscopy for the Differentiation of Subacute Cutaneous Lupus Erythematosus from Other Erythematous Desquamative Dermatoses-Psoriasis, Nummular Eczema, Mycosis Fungoides and Pityriasis Rosea

Subacute cutaneous lupus erythematosus (SCLE) is a condition that might pose a diagnostic challenge. The aim of this study was to assess the usefulness of videodermoscopy in the differentiation of SCLE from other erythematous-desquamative dermatoses. Consecutive patients with SCLE (n = 27), psoriasis (n = 36), nummular eczema (n = 30), mycosis fungoides (n = 26), and pityriasis rosea (n = 20) referred to our Department of Dermatology were recruited for this study. A representative lesion was visualized using a Canfield D200EVO Videodermatoscope (Canfield Scientific GmbH, Bielefeld, Germany) and evaluated for the following parameters: vessels (morphology and distribution), scales (color and distribution), follicular findings, colors and morphologies, and presence of specific clues. SCLE was predominantly characterized by a polymorphous vascular pattern (92.6%) of unspecific distribution (92.6%) over a pink-red background (74.1%). Gray-brown dots were present in 10 (37.0%) cases, and pigmentation was noted in 15 (55.6%) patients, including peripheral pigmentation in 7 (25.9%) patients. Videodermoscopic evaluation showed significant differences between SCLE and psoriasis, which was characterized by regularly distributed dotted vessels. Although some common dermoscopic features with MF were noted, the presence of yellow structureless areas and red dots/globules favored the diagnosis of MF. In conclusion, a polymorphic vascular pattern, especially in association with gray-brown dots and/or peripheral pigmentation, is a valuable clue for the differentiation of SCLE from other erythematous-desquamative dermatoses.

Cutaneous Toll-like Receptor 9 Pre-Defines Hydroxychloroquine Dosage in Patients with Both Discoid and Subacute Lupus Erythematosus

Background and Objectives: Cutaneous lupus erythematosus (CLE) presents clinically heterogeneous manifestations, partially explained by the different expression of Toll-like receptors (TLRs) type 8 and 9, located to endosomal compartments where they are poised to recognize microbial nucleic acids. This disease is empirically treated with hydroxychloroquine (HCQ), which is hallmarked with a safe and effective profile, but induces a slow and sometimes clinically insufficient therapeutic response. Currently, no biomarkers predictive of response are validated or even proposed in the scientific literature. We aimed to evaluate endosomal TLR type 7, 8 and 9 as predictive biomarkers of HCQ efficacy. Materials and Methods: We conducted a case-control study comparing CLE patients retrospectively assigned to three subgroups based on 3-6-month Cutaneous LE Disease Area and Severity Index (CLASI) reduction upon treatment with HCQ (I = <40% vs. II = 40-80% vs. III = >80%). Before HCQ, lesional skin specimens were collected in untreated CLE and through immunohistochemistry; TLR-7, -8 and -9 expression was evaluated in the epidermis and the lymphocytic infiltrate was evaluated in the dermis. Results: Sixty-six lesional skin biopsies were compared with healthy controls. CLE patients displayed lower epidermal expression of total TLR 8 and 9 as well as infiltrating TLR-8, TLR9 + lymphocytes compared to controls. High HCQ responders differed from low responders for TLR-9 positivity (high vs. low) and for the lymphocytic dermal infiltrate (high vs. low). Conclusions: TLR9 could be envisaged as a possible biomarker to predict HCQ response level and dosage in CLE patients.