Systemic Lupus Erythematosus
The manifestations of this multisystem disorder range from relatively benign, self-limited cutaneous involvement to severe, potentially fatal systemic illness. Skin lesions associated with lupus erythematosus (LE) are classified histologically as LE-specific or LE-nonspecific.LE-specific lesions. These are further categorized as acute, subacute, or chronic. The most characteristic and well-known acute skin sign of systemic lupus erythematosus (SLE) is the "butterfly" rash; however, it occurs in only 40% of patients. The rash (A), which is commonly precipitated by sunlight, consists of erythematous papules and plaques in a malar distribution. Immunofluorescent staining typically reveals immune deposits of primary IgM at the dermal-epidermal junction.1Other acute lesions of LE includegeneralized erythema and, rarely, bullous lesions. These lesions mimic extensive burns and, depending on the extent of involvement, can be lifethreatening. They are caused by basement membrane antibodies against type IV collagen( and clinically and histologically resemble dermatitis herpetiformis.2More than half of patients with SLE have photosensitivity that can lead to subacute cutaneous lesions and can also exacerbate systemic disease. These lesions are nonscarring and do not produce atrophy. They start as erythematous papules or small plaques with scale and evolve into either polycyclic plaques with central clearing or papulosquamous lesions that resemble psoriasis or lichen planus (B). To help reduce the risk of subacute cutaneous lesions, advise patients to always cover exposed areas with sunscreen that has a sun protection factor of at least 15. The most common chronic skin manifestations of LE are discoid lesions (C). These round, well-demarcated lesions are characterized by erythema, telangiectasia, adherent scale, follicular plugging, dyspigmentation, atrophy, and scarring. Discoid lesions can be distributed locally, usually on the head or neck, or widely, involving any part of the body. Patients seldom, if ever, have systemic symptoms. Except for their associated atrophy and scarring, discoid lesions are similar to those of subacute LE.LE-nonspecific lesions. Alopeciais a common finding in SLE (D). It can be transient (related to disease exacerbations) or permanent (secondary to the scarring of disseminated LE). Mucous membrane lesions may cause ulcers of the mouth, nose, or other mucocutaneous surface.Cutaneous vasculitic lesions appear as palpable purpura, subcutaneous nodules, splinter hemorrhages, telangiectasia, palmar erythema, or nailfold ulcerations.