Dx: Generalized chronic cutaneouslupus erythematosus
The clinical features of our patient were most consistent with generalized chronic cutaneous lupus erythematosus (CCLE), which is 1 of 3 subtypes of cutaneous lupus erythematosus (CLE). The other 2 are acute and subacute cutaneous lupus erythematosus (ACLE and SCLE, respectively). CCLE is further divided into 3 distinct entities: discoid lupus erythematosus (DLE), chilblain lupus erythematosus, and lupus erythematosus panniculitis.
Distinguishing between the different forms of cutaneous lupus can be challenging; diagnosis is based on differences in clinical features and duration of skin changes, as well as biopsy and lab results.1 The clinical features of our patient were most consistent with DLE, based on the scarring alopecia with scaly atrophic plaques, dyspigmentation, and exacerbation following sun exposure.
DLE is the most common form of CCLE and frequently manifests in a localized, photosensitive distribution involving the scalp, ears, and/or face.2 Less commonly, it can demonstrate a more generalized distribution involving the trunk and/or extremities (reported incidence of 1.04 per 100,000 people).3 Longstanding DLE lesions commonly exhibit scarring and dyspigmentation. DLE occurs in approximately 15% to 30% of SLE patients,4 whereas about 10% of patients with DLE will progress to SLE.3
Positive antinuclear antibodies (ANA) are found in 54% of patients with CCLE, compared to 74% and 81% of patients with SCLE and ACLE, respectively.5 Thus, a negative ANA should not rule out the possibility of CLE.
Comprehensive lab work and biopsy could expose a systemic origin
While our patient already had a diagnosis of SLE, many patients will present with no prior history of autoimmune connective tissue disease, and, in that case, the objective should be to confirm the diagnosis and evaluate for systemic involvement. This includes a thorough review of systems; skin biopsy; complete blood count; liver function tests; urinalysis; and measurement of creatinine, inflammatory markers, ANA, extractable nuclear antigens, double-stranded DNA, complement levels (C3, C4, total), and antiphospholipid antibodies.6
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