Acute Cutaneous Lupus Erythematosus (ACLE) Workup

Updated: May 10, 2017
  • Author: Fnu Nutan, MD, FACP; Chief Editor: William D James, MD  more...
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Workup

Approach Considerations

Because acute cutaneous lupus erythematosus (ACLE) and systemic lupus erythematosus (SLE) are associated closely, it is safe to assume that the laboratory findings in SLE closely mirror the findings in ACLE.

Diagnostic data from laboratory tests are supported by histopathologic examination of the skin. Further diagnostic substantiation is obtained by performing immunofluorescent examination of skin lesions.

The most striking histologic change in ACLE is the presence of edema involving upper dermis and focal liquefactive degeneration of the basal cell layer. Cellular dermal infiltrate is sparse and consists of lymphocytes. In extreme cases, dissolution of the basal layer occurs secondary to extensive vacuolization, forming a subepidermal bulla. [13]

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Laboratory Studies

As previously mentioned, antinuclear antibody (ANA) assay results invariably are positive in patients with systemic lupus erythematosus (SLE) and, therefore, in patients with acute cutaneous lupus erythematosus (ACLE). The peripheral rim pattern is associated most strongly with lupus erythematosus, although other patterns commonly are present. ANA results are less likely to be positive in dermatomyositis, which mimics lupus erythematosus both clinically and histologically.

Anti–double-stranded deoxyribonucleic acid (DNA) antibody (anti-dsDNA) assay is specific for SLE and is present in 60-80% of patients with ACLE, often in high titers.

Complement levels usually are depressed in patients with ACLE.

Anti-Sm antibody assay has a strong specificity for SLE; therefore, perform this assay to exclude underlying systemic involvement. This is particularly relevant in patients in whom anti-dsDNA results are negative.

Ro (SS-A) antibodies are often correlated with cutaneous involvement in subacute cutaneous lupus erythematosus (SCLE). However, almost a third of Ro antibody–positive patients with ACLE present with kidney involvement, particularly young female patients. [14]

A positive rheumatoid factor and speckled ANA pattern may be seen in association with Rowell syndrome. [9]

Low-specificity tests include the following:

  • U1 ribonucleoprotein antibody assay - Results are positive in mixed connective-tissue disease, which sometimes manifests as a malar eruption

  • Complete blood cell (CBC) count - Anemia, leukopenia, and/or thrombocytopenia may be seen in patients with ACLE who have systemic involvement

  • Erythrocyte sedimentation rate - Although a nonspecific marker, marked elevations in levels indicate possible systemic involvement

  • Urinalysis - Proteinuria, hematuria, and urine casts are indicative of underlying nephritis

  • Creatinine and blood urea nitrogen (BUN) levels - Elevation indicates renal compromise

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