Lupus at a Glance
- A group of heterogeneous illnesses that have in common the development of immunity to self-nucleic acids and their associated proteins, with skin-only disease at one end of the spectrum and severe visceral involvement at the other.
- Skin lesions may be specific to lupus or nonspecific and are seen in other conditions as well.
- Acute cutaneous lupus erythematosus (malar rash) is almost always associated with underlying visceral involvement, subacute cutaneous lupus patients meet systemic lupus erythematosus criteria about 50% of the time (but typically express only mild systemic clinical manifestations), and chronic cutaneous lupus (discoid lupus erythematosus, lupus panniculitis, chilblain lupus, and tumid lupus erythematosus) patients most often have skin-only or skin-predominant disease.
- Discoid lupus erythematosus causes scarring and can be permanently disfiguring. Subacute cutaneous lupus and acute cutaneous lupus erythematosus are highly photosensitive and are characteristically nonscarring.
- Lupus erythematosus-nonspecific skin lesions include nonscarring alopecia, mouth ulcers, photosensitivity, Raynaud's phenomenon, and vasculitis/vasculopathy, among others. They often herald a systemic lupus erythematosus flare.
- Treatment consists of sunscreens, local and systemic (short-term) glucocorticoids, antimalarials, retinoids, immunosuppressives, thalidomide, and biologic therapies.
- Lupus erythematosus occurs much more commonly in women (9:1 female-male ratio).
- Both systemic lupus erythematosus and cutaneous lupus erythematosus are associated with upregulation of class I interferon signaling.
Lupus erythematosus (LE) is the root designation for a diverse array of illnesses that are linked together by the development of autoimmunity directed predominantly at the molecular constituents of nucleosomes and ribonucleoproteins. Some patients present with life-threatening manifestations of systemic LE (SLE); whereas others, who are affected with what likely represents the same basic underlying disease process, express little more than discoid LE (DLE) skin lesions throughout their illness. It is convenient to conceptualize LE as a clinical spectrum ranging from mildly affected patients with only localized DLE skin lesions to those at risk of dying from the systemic manifestations of LE such as nephritis, central nervous system disease, or vasculitis. The pattern of skin involvement expressed by an individual patient with LE can provide insight about the position on the spectrum where the patient's illness might best be placed.
The nomenclature and classification system originally devised by James N. Gilliam divides the cutaneous manifestations of LE into those lesions that show characteristic histologic changes of LE (LE-specific skin disease) and those that are not histopathologically distinct for LE and/or may be seen as a feature of another disease process (LE-nonspecific skin disease). Within this context, the term “LE-specific” relates to those lesions displaying an interface dermatitis. The term cutaneous LE (CLE) is often used synonymously with “LE-specific skin disease” as an umbrella designation for the three major categories of LE-specific skin disease: acute cutaneous LE (ACLE), subacute cutaneous LE (SCLE), and chronic cutaneous LE (CCLE). This will be the framework used in our discussion of the extraordinarily diverse set of cutaneous lesions that occur in patients with LE (Table 155-1).