Manifestations and Treatment of Cutaneous Lupus Erythematosus (Part I of II)
Cutaneous lupus erythematosus (CLE) comprises a clinically heterogeneous group of lesions that share histopathologic characteristics and can have an association with systemic lupus erythematosus (SLE). Recognition and treatment of CLE is important, because it is both a disease in its own right with significant morbidity to those who suffer from it1 and a potential sign of systemic disease (Table 1). The common clinical manifestations of CLE, their differential diagnoses, and both the established and novel treatments for CLE will be reviewed.
Classification of Lupus Erythematosus Lesions
Creating a classification scheme for the cutaneous manifestations of lupus erythematosus (LE) is difficult because of the variety of CLE and SLE lesions and our incomplete understanding of its pathophysiology.2 The Gilliam and Sontheimer classification divides LE into specific lesions that are only seen in LE and nonspecific lesions which are not limited to LE. Each of these specific lesions has a unique clinical appearance but share common histopathologic features. Vacuolar degeneration of dermo-epidermal interface, perivascular infiltrates and periadnexal infiltrates are present in all LE specific lesions except for lupus erythematosus tumidus (LET),
which does not have vacuolar degeneration. The LE specific lesions are further organized by their chronicity. The Gilliam and Sontheimer classification, although favorable for research, has limited clinical utility.3 However, given the widespread use of this classification scheme and the lack of an accepted alternative, the Gilliam and Sontheimer classification is used here.
Acute Cutaneous Lupus Erythematosus
Erythematous macules or edematous plaques in a malar (butterfly) distribution are the classic findings in acute cutaneous LE (ACLE) (Figure 1). Lesions are not limited to the face and may occur in any sun-exposed area (e.g., extensor surfaces and hands) and tend to spare sun-protected areas, including the nasolabial folds and mid-anterior neck. Depending on the distribution of lesions, the terms localized or generalized may be used to modify the diagnosis of ACLE. However, this distinction has no pathologic significance. ACLE appears abruptly, often several days after sun exposure and can last for hours to days. In rare cases, an extensive inflammatory infiltrate can form papules, vesicles or bullae. Nonspecific LE lesions and subacute cutaneous LE (SCLE) [discussed below] may be seen concurrently with ACLE. Only rarely are discoid LE (DLE) and ACLE seen simultaneously. Of all the forms of CLE, ACLE is most closely associated with SLE and, when found, may indicate active or imminent SLE.
The differential diagnosis of ACLE includes rosacea, dermatomyositis, drug or photo hypersensitivity, and erythema multiforme. In fact, there can be EM in the setting of LE, which is referred to as Rowell syndrome. Dermatomyositis is the most challenging to differentiate from ACLE (and SCLE as well) as the lesions can clinically resemble LE and are histologically similar. Findings of muscle weakness, Gottrons papules, sparing of the interphalangeal creases, dilated nailfold capillaries, and frayed cuticles (samitz sign) can aid in the clinical diagnosis. Both LE and DM can be serologically positive for ANA, however the absence of anti-dsDNA, -Sm, -RNP, -Ro/SS-A and -La/SS-B antibodies in dermatomyositis are helpful in differentiating these two conditions.4
Subacute Cutaneous Lupus Erythematosus
SCLE begins as symmetrically distributed superficial erythematous papules. The lesions are exquisitely photosensitive and predominantly occur in sun-exposed areas, but the central face