• Systemic lupus erythematosus (SLE) is a chronic, idiopathic, multisystemic, autoimmune disease associated with polyclonal B-cell activation.

• Fibrinoid degeneration of connective tissue and the walls of blood vessels associated with an inflammatory infiltrate involving various organs may result in arthralgia or arthritis, kidney disease, liver disease, central nervous system disease, gastrointestinal disease, pericarditis, pneumonitis, myopathy, splenomegaly, as well as skin disease.

• The cutaneous manifestations of SLE result from the production of multiple autoantibodies that deposit immune complexes at the dermal-epidermal junction.

• Lupus skin lesions may be classified into three distinct groups:

• Acute cutaneous lupus erythematosus (ACLE) lesions are strongly associated with active SLE; however, ACLE lesions may occasionally be seen in subacute cutaneous lupus erythematosus (SCLE).

• SCLE comprises the second category.

• Chronic cutaneous lupus erythematosus (CCLE) traditionally referred to as discoid lupus erythematosus (DLE). DLE lesions may be seen in both SLE and CCLE.

• SLE is seen in a 9:1 female-to-male ratio; it is more common in blacks and Hispanics.

• Approximately 10% of patients with SLE have a first-degree relative with the disease. An association of lupus and human leukocyte antigens (HLA) -DR2 and -DR4 has been seen.

The following are considered to be SLE-specific skin lesions:

• The classic malar or “butterfly” rash (Fig. 34.15) is a persistent erythema over the cheeks that tends to spare the nasolabial creases. Sometimes, this is the initial symptom of lupus, and it often occurs after sun exposure.

• Photosensitivity occurs as an exaggerated or unusual reaction to sunlight. Lesions tend to occur in sun-exposed areas such as the face, dorsa of the forearms, the hands, and the sun exposed “V” of the neck.

• Discoid lesions (discoid lupus erythematosus) are erythematous lesions that evolve into scaly, atrophic scarring plaques (Fig. 34.16). Such discoid lesions affect 10% to 15% of patients with SLE.

• Oral ulcerations may develop, more often on the hard palate or nasopharynx.

• Nonspecific lesions of lupus that may be seen in SLE and other connective tissue diseases include the following:

• The “spider” type of telangiectasia is usually seen in SLE, scleroderma, as well as dermatomyositis.

• On dorsal hands, violaceous plaques that spare the skin overlying the joints are characteristic of SLE. Conversely, in dermatomyositis, the skin over joints are affected (Gottron papules [see 34.26 below]).

• Periungual telangiectasias are seen in SLE (Fig. 34.17), as well as in dermatomyositis and scleroderma.

• Palmar telangiectasias, palmar erythema.

• Livedo reticulitis (Fig. 34.18), panniculitis, thrombophlebitis, urticaria, urticarial vasculitis, frontal alopecia (“lupus hair”) and diffuse nonscarring alopecia, and bullae are associated primarily with SLE.

• Vasculitis, palpable purpura, and vasculitic ulcers (Figs. 34.19 and 34.20).

• Raynaud phenomenon is associated with SLE and scleroderma.

According to the American Rheumatologic Association, a person is considered to have SLE if four or more of the following criteria are present:

• “Butterfly” rash

• Lesions of CCLE or DLE

• Photosensitivity

• Oral ulcers

• Arthritis in two or more joints

• Serositis

• Renal disorder

• Neurologic disorder

• Hematologic disorder

• Immunologic disorder: anti-DNA, anti-Smith (anti-Sm) antibody, or a false-biologic-positive syphilis serologic result

• Antinuclear antibodies (ANAs)

• Fatigue, fever, and malaise may be the presenting nonspecific symptoms.

• Signs or symptoms related to the specific organ or area involved (e.g., arthralgia).

• Associated hematologic abnormalities: idiopathic thrombocytopenic purpura, hemolytic anemia, leukopenia, and clotting abnormalities, which may be related to the anticardiolipin syndrome.

• Other associated conditions and symptoms that may be noted include rheumatoid arthritis, Sjögren syndrome, seizures, and the occurrence of multiple spontaneous abortions.

• Antinuclear antibody (ANA) titers are positive in 95% of patients with SLE. The peripheral rim pattern is associated most strongly with lupus erythematosus, although other patterns commonly are present.

• Anti-dsDNA (antibody to native double-stranded DNA) is present in 60% to 80% of patients and is more specific for SLE.

• Anti-Sm antibody has a strong specificity for SLE. This is particularly relevant in patients in whom anti-dsDNA results are negative and may help exclude underlying systemic involvement.

• Antiphospholipid antibodies are present in 25% of patients.

• The erythrocyte sedimentation rate is usually elevated.

• Hypocomplementemia occurs in 70% of patients and is noted especially when there is renal involvement in active SLE.

• The lupus band test involves the direct immunofluorescence of uninvolved, non-sun-exposed skin. When positive, it is suggestive of the presence of renal disease. This test has been largely supplanted by the aforementioned serologic tests.