Discoid Lupus Erythematosus

Updated: Jun 11, 2020
  • Author: Ruth Ann Vleugels, MD, MPH; Chief Editor: William D James, MD  more...
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Overview

Background

Cutaneous lupus erythematosus (CLE) can be divided into three main subtypes: acute, subacute, and chronic, all of which demonstrate photosensitivity. Acute cutaneous lupus erythematosus (ACLE) most commonly presents as symmetric erythema overlying the malar cheeks and nasal bridge with sparing of the nasolabial folds (butterfly rash). However, it can also present as a diffuse morbilliform eruption with erythema and edema of the hands, with prominent sparing of the joints. Subacute cutaneous lupus erythematosus (SCLE) characteristically presents as annular or psoriasiform plaques in a photodistribution. Chronic cutaneous lupus erythematosus (CCLE) can be further divided into three main types: discoid lupus erythematosus (DLE), tumid lupus, and lupus panniculitis. Tumid lupus typically presents with juicy papules and plaques that lack scale and heal without scarring, whereas lupus panniculitis involves the subcutaneous tissue, leading to painful subcutaneous nodules that heal with depression and atrophy.

DLE classically presents with erythematous-to-violaceous, scaly plaques with prominent follicular plugging that often results in scarring and atrophy (see the images below). DLE may occur in the absence of systemic disease, or it may occur in association with systemic lupus erythematosus (SLE).

Discoid lupus erythematosus on the face. Discoid lupus erythematosus on the face.
Chronic scarred lesion of discoid lupus erythemato Chronic scarred lesion of discoid lupus erythematosus.

The risk of progression to SLE in patients with DLE has been demonstrated to be higher than previously reported. The reported rates were 16.7% progression to SLE within 3 years of diagnosis in one international study and 17% progression within a mean time of 8 years in a second study, [1, 2] as compared with previous data indicating that less than 5-10% of patients with DLE progress to SLE. [3] The reported interval from DLE diagnosis to SLE onset has varied widely, with a mean time to progression of approximately 8 years in one study, with another small cohort study reporting the median time to progression from DLE to SLE of 453 days. [4] Overall, patients with DLE rarely fulfill four or more of the 17 Systemic Lupus International Collaborating Clinics (SLICC) criteria used to classify SLE. [5] Serologic abnormalities are uncommon.

Therapy with photoprotection, topical corticosteroids, and antimalarial agents is often effective. However, immunosuppressive and/or immunomodulatory agents may be required for recalcitrant disease (see Treatment and Medication).

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Etiology

Lupus erythematosus is a polygenic autoimmune disease linked to various HLA subtypes, immune signaling, and environmental factors, which ultimately leads to autoantibody production and T-cell dysfunction. However, the exact etiology of discoid lupus erythematosus (DLE) is not well understood. DLE likely occurs in genetically predisposed individuals, but the exact genetic connection has not been determined. It has been suggested that a heat-shock protein is induced in the keratinocyte following ultraviolet (UV) light exposure or stress, and this protein may act as a target for gamma (delta) T-cell–mediated epidermal cell cytotoxicity. Additionally, toll-like receptors may be involved in the pathogenesis. [6]

Emerging research has shown a role for interferons and JAK-STAT (Janus kinase/signal transducers and activators of transcription) signaling in DLE, postulating the potential for treatment with JAK inhibitors. [7] Additionally, fibrosis in DLE has been linked to transforming growth factor (TGF)–β signaling, providing another molecular target for therapy. [8] The overexpression of two microRNAs (miR-31 and miR-485-p) has also been reported to contribute to DLE pathogenesis. [9]

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Epidemiology

Worldwide, the prevalence of systemic lupus erythematosus (SLE) ranges from 17-48 cases per 100,000 population. The highest prevalence of SLE occurs in persons aged 40-60 years, with SLE onset most often occurring in patients in their 20s and 30s. SLE is approximately 10 times more common in women than in men. [10]

In Europe and the United States, the incidence of isolated cutaneous lupus erythematosus (CLE) has ranged from 4 to 4.3 cases per 100,000 population, slightly higher than the incidence of SLE (approximately 3 cases per 100,000 population). [1, 10, 11] In a 2015 epidemiological study from Olmstead County, Minnesota, Jarukitsopa et al demonstrated that the incidence of CLE rises steadily with age, peaking at age 60-69 years. [11]

Discoid lupus erythematosus (DLE) is responsible for 50-85% of cases of CLE and occurs 2-3 times more frequently in women than in men. DLE has also been reported to have a higher incidence in African Americans than in whites. Although DLE may occur at any age, it most often develops in persons aged 20-40 years.

A limited number of population-based studies have estimated the incidence of DLE in the absence of SLE (“primary” DLE). [12, 13] In a 2019 epidemiological study using the Georgia Lupus Registry, Drenkard et al reported an overall age-adjusted DLE incidence of 3.7 cases per 100,000 person-years among Georgia residents. [12]

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Prognosis

Although the prognosis of patients with discoid lupus erythematosus (DLE) is favorable regarding mortality, morbidity can be considerable. Patients may experience pain or burning of their lesions, or occasionally pruritus. Many patients with DLE experience disfigurement from the scars or atrophy that can develop. Scarring alopecia is particularly disturbing for patients. Prompt treatment of early lesions may help prevent or lessen the severity of scarring and atrophy. Discoid lupus erythematosus is known to negatively impact patient quality of life. [14] In fact, a 2016 study demonstrated that over one third of patients with cutaneous lupus met criteria for depression or anxiety with need for psychiatric intervention. [15] Furthermore, a significant correlation has been found between skin disease activity in cutaneous lupus and quality of life. [16]

Exacerbation is common with increased sun exposure, particularly in the spring and summer. Serious systemic disease is rare, but when it occurs, patients may develop life-altering sequelae. Malignant degeneration within DLE lesions is uncommon, but may occur. Hence, prompt biopsy of suggestive lesions developing within chronic DLE lesions is warranted. [17, 18]

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Patient Education

Instruct patients in sun-avoidance techniques and the proper use of sunscreens, wide-brimmed hats, and protective clothing. Advise patients to quit smoking. Discuss the possibility of systemic involvement with patients. Pamphlets from the Lupus Foundation of America, Inc and JAMA Dermatology Cutaneous Lupus Patient Page [19] concerning skin disease and photosensitivity are useful adjuncts to verbally delivered information. Also see Prognosis and Treatment.

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