Lupus erythematosus (LE) is a group of diverse, persistentautoimmuneinflammatory diseases.
Systemic lupus erythematosus (SLE) affects several organs (such as skin, joints and kidneys) and blood tests reveal circulating autoantibodies. The clinical features of SLE are highly variable and may overlap with other diseases and conditions. Skin involvement or cutaneous lupus (CLE) affects 80% of patients with SLE.
SLE is sometimes called acute lupus erythematosus, and the cutaneous features may be described as acute cutaneous lupus.
What causes systemic lupus erythematosus?
Factors leading to SLE include:
Geneticpredisposition, including haplotype HLA-B8, -DR3
SLE can affect males and females of any age. Every year about 2–7 new cases are diagnosed in a population of 100,000 people. SLE is much more common in females than males, and onset is most often between the ages of 15 and 45 years.
SLE is more prevalent and more severe in smokers. Smoking also reduces the effectiveness of antimalarials and other therapies.
Autoantibodies can be present in people that have no manifestation of the disease.
What are the cutaneous features of systemic lupus erythematosus?
About 80% of patients with SLE have skin involvement (cutaneous LE), and it is the first sign of SLE in about one-quarter of them. It can present as LE-specific or LE-nonspecific manifestations. LE-specific lesions tend to be induced or aggravated by exposure to ultraviolet radiation and are localised in sun-exposed sites such as the face, neck, V of the neck and upper back.
Specific cutaneous SLE
Cutaneous lupus (CLE) has specific acute, subacute and chronic manifestations.
Only 5% of patients with chronic CLE have SLE, as CLE presents as a skin problem without the involvement of other organs.
Acute CLE
Central face malar or "butterfly" violaceouserythema with a sharp cutoff at lateral margins, resolves without scarring (may result in persistent telangiectasia)
Mucosalerosions and ulcerations (lips, nose, mouth, genitals)
Photosensitivity: lupus rashes are mainly on sun-exposed sites. Photosensitivity can be mild to very severe with the rash appearing after minimal light exposure.
Diffusehair loss (nonscarring alopecia) with brittle hair shafts
Nonspecific cutaneous SLE refers to features relating to underlying illness rather than an autoimmune attack. These features may occur in other connective tissue and autoimmune diseases.
Blood: reduced numbers of red cells, white cells and platelets
How is systemic lupus erythematosus diagnosed?
SLE can be difficult to diagnose at times because of the great variety of presentations of the disease, and the presence of similar symptoms in people that do not have the disease. Several attempts have been made to help clinicians reach the diagnosis, including the American College of Rheumatology criteria for the classification of SLE (revised in 1997). In 2012, the criteria were revised by the Systemic Lupus International Collaborating Clinics (SLICC).[1]
Using the SLICC criteria, SLE is diagnosed if the patient has either of the following over time:
Four criteria including ≥ one clinical criterion and ≥ one immunological criterion
Biopsy-proven lupus nephritisand antinuclear antibodiesor anti-double-stranded DNA antibodies
These criteria depend on history, clinical examination, exclusion of other causes of the symptoms, and the results of investigations—including blood tests and biopsy of the affected tissue. Four of the 17 SLICC criteria relate to the skin.
* SLICC Systemic Lupus International Collaborating Clinics; ANA antinuclear antibody; anti-dsDNA anti-double-stranded DNA
Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI)
The Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI) was developed in an attempt to classify the severity of CLE. [2] A score of activity and damage due to the disease is calculated in each of 12 anatomical locations (refer to the original published paper for details).
The total activity score is made up of:
The degree of redness (0–3) and scale (0–2)
Mucous membrane involvement (0–1)
Recent hair loss (0–1), nonscarring alopecia (0–3)
Total damage score is made up of:
The degree of dyspigmentation (0–2), and scarring (0–2)
Persistence of dyspigmentation more than 12 months doubles the dyspigmentation score
Direct immunofluorescence is positive in sun-protected healthy skin in SLE
Blood tests
Multiple autoantibodies are typically present in SLE, often in high titre (see immunological criteria above). Relating to skin disease in SLE:
About 70% of patients with subacute CLE have positive extractable nuclear antibodies anti-Ro (also called anti-SSA) and anti-La (also called anti-SSB).
Anti Ro/La is also associated with Sjögren syndrome and risk of neonatal lupus erythematosus.
Anti-annexin 1 antibodies may be a diagnostic marker for discoid CLE
Patients with SLE should also have renal, liver and thyroid function and markers of inflammation performed, such as C-reactive protein (CRP), immunoglobulins and rheumatoid factor.
Photoprovocation tests
Photoprovocation tests are sometimes carried out to confirm that a skin eruption is precipitated by exposure to particular wavelengths of ultraviolet or visible radiation.
Other tests
Other tests depend on which organ is affected. They may, for example, include:
Urine tests for hyaline casts, creatinine, protein and blood
Blood pressure
Chest X-ray, ultrasound, CT and MRI scans
Electrocardiograph (ECG) and echocardiography
Nerve and muscle testing
Ophthalmological examination
Endoscopy of the gastrointestinal tract
Kidney biopsy.
What is the treatment for systemic lupus erythematosus?
Preventative measures
The following measures are essential to reduce the chance of flares and organ damage.
Treatment of SLE depends on which are the predominant organs involved in the disease. Typically, any of the following drugs may be used alone or in combination.
Systemic corticosteroids, such as prednisone or prednisolone. These are the mainstay of treatment in a seriously ill patient with acute LE.
Targeted biologic therapies under evaluation for SLE include anifrolumab, belimumab (intravenous and subcutaneousformulations were registered by FDA for use in SLE in 2017) and off-label rituximab, abatacept, tocilizumab and eculizumab.[3]
What is the outlook for systemic lupus erythematosus?
SLE leads to a chronic illness with flares and periods of remissions. In some patients, all signs of active disease resolve in time.
References
Petri M, Orbai AM, Alarcón GS et al. Derivation and validation of the Systemic Lupus International Collaborating Clinics classification criteria for systemic lupus erythematosus. Arthritis Rheum 2012; 64: 2677–86. DOI: 10.1002/art.34473. PubMed PMID: 22553077; PubMed Central
Albrecht J, Werth VP. Clinical outcome measures for cutaneous lupus erythematosus. Lupus 2010; 19: 1137–43. doi: 10.1177/0961203310370049. Review. PubMed PMID: 20693208; PubMed Central
Belmont HM. Treatment of systemic lupus erythematosus – 2013 update. Bull Hosp Jt Dis 2013; 71: 208–13. Review. PubMed