Systemic Lupus Erythematosus (SLE)
Definition and Epidemiology:
Lupus Erythematosus is an autoimmune multisystem disorder that often affects the skin and other organs such as Kidneys, joints and heart. The cutaneous manifestations can be a source of disability.
Systemic lupus Erythematosus (SLE) is a common disease with significant morbidity and mortality. The reported prevalence of SLE in the United states is 20 to 150 cases per 100,000. The strongest affecting risk factor is gender. The increased frequency of SLE in women especially in the childbearing age has been attributed to the estrogen hormonal effect.
Ethnicity is also a major risk factor. The prevalence of SLE in African American women is fourfold higher than Caucasian women. In addition, African American and Hispanic individuals in the US have a poorer renal prognosis than Caucasian individuals.
Pathogenesis:
The pathogenesis of SLE is complex and multifactorial. It involves the interaction between genetic and environmental factors. The genetic factors include HLA-B8-DR3 and The environmental factors include ultraviolet radiation, medications, cigarette smoking and possibly viruses. This interplay triggers an inflammatory cascade of cytokines, chemokines and inflammatory cell response that ends with cytotoxic keratinocyte damage.
Clinical features:
Discoid Lupus Erythematousus: discoid lesions represents one of the most common skin manifestations of lupus and commonly found on the face, scalp and ears. Discoid lesions has the potential of scarring, and over time, a substantial portion of patients develop disfiguring scars. Active lesions are intensely inflammatory with a pronounced superficial and deep dermal infiltrate. On palpation, they feel thicker and firmer than surrounding skin. The adnexa are prominently involved, with follicular plugging and scarring alopecia. Dyspigmentation is a common complication in longstanding lesions, with hypopigmentation in the center and hyperpigmentation in the periphery.
Subacute Cutaneous Lupus Erythematosus: patients with subacute cutaneous lupus Erythematosus (SCLE) typically exhibit photosensitivity. Their lesions most frequently occur in sun-exposed areas. Lesions of SCLE may have an annular configuration with raised pink borders and central clearing, or a papulosquamous presentation with chronic psoriasiform or eczematous appearance.
In 20-30% of patients with SCLE, the disease is linked to medications including terbinafine, thiazide diuretics, anti-TNF, and proton pump inhibitors.
Since Anti-SSA/Ro antibodies are associated with both Sjogren syndrome and SCLE. Some patients have features of both diseases and may have some internal manifestations of Sjogren such as pulmonary or neurologic disease.
Acute Cutaneous Lupus Erythematosus: the lesions of ACLE are exemplified by the development of Malar rash (“butterfly rash”). These lesions tend to be transient following sun exposure and resolve without scarring. Patients presenting with this type of eruptions must be carefully evaluated for internal manifestations.
The morphology of lesions ranges from mild erythema to intense edema. The face is most commonly affected and there is often sparing of the nasolabial folds.
Lupus panniculitis: intense inflammation of the subcutaneous tissue leading to indurated plaques that can evolve into disfiguring, depressed areas. Lesions are frequently distributed over the face, scalp, upper arms, breast and thighs.
Chilblain lupus: chilblain lupus consists of dusky purple papules and plaques on the toes, fingers and sometimes the nose. These lesions are exacerbated by cold exposure.
Systemic manifestations: the organ systems that are commonly affected are joints, kidneys, hematologic and Central nervous system as well as pleural and pericardial serosal surfaces. Many of the internal organs manifestaitons are included in the diagnostic criteria.
Diagnosis:
Diagnostic criteria: using the SLICC criteria, SLE is diagnosed if the patient has either of the following:
- Four criteria including at least more than one clinical criterion and one immunological criterion
- Biopsy proven lupus nephritis and antinuclear antibody (ANA) or anti double stranded DNA anitbody
Clinical criteria
- Acute or subacute cutaneous lupus
- Chronic cutaneous lupus (discoid, lupus panniculitis)
- Oral ulcers
- Nonscarring alopecia
- Synovitis involving 2 or more joints
- Serositis involving lungs and heart
- Renal involvement
- Neurological involvement
- Hemolytic anemia
- Leukopenia or lymphopenia
- Thrombocytopenia
Immunological criteria:
- Raised ANA titers
- Raised Anti-double stranded DNA
- Presence of anti smith antibody
- Positive antiphospholipid antibody
- Low complement levels
- Positive direct Coombs test
Management:
General measures:
- Sun protection using clothing, accessories and SPF 50+ sunscreens.
- Smoking cessation
Topical treatments:
- Topical and intralesional corticosteroids are a mainstay of therapy. They offer a high degree of safety profile as well as a relatively rapid response. Particularly in active discoid lesions, intralesional triamcinolone can be very effective.
- Topical calcineurin inhibitors such as Tacrolimus can also be used.
Systemic treatments:
- Antimalarials such as hydroxychloroquine remains the gold standard for systemic therapy.
- Systemic corticosteroids such as prednisone. These are the mainstay of treatment in acutely ill patients.
- Methotrexate
- Immunosuppressive agents such as azathioprine, mycophenolate and cyclophosphamide
- Targeted biological treatments that have been FDA approved such as anifrolumab and belimumab
Written by:
Bandar Alharbi, Medical Intern.
Revised by:
Naif Alshehri, Medical Intern
Resources:
Dermnet
UpToDate
Bolognia