Chapter 22 Autoimmune connective tissue diseases
1. Discuss the skin changes of lupus erythematosus.
Skin changes occur very frequently in lupus erythematosus (LE) and are second in frequency only to musculoskeletal complaints in this condition, occurring in about 85% of patients. It is useful to classify the eruptions seen in LE as to their possible diagnostic and prognostic significance. Skin lesions that are diagnostic of LE have been called lupus-specific eruptions. Skin biopsies of these lesions show characteristic histopathologic changes of cutaneous LE. Further classification of the lupus-specific eruptions into subtypes of cutaneous LE is also useful, as some lesions of cutaneous LE are more strongly associated with systemic lupus erythematosus.
Lupus patients also develop many skin changes that are not specific for LE, termed lupus-nonspecific eruptions (Table 22-1). These eruptions do not help to establish a diagnosis of LE, but they may still be very important to note, as specific systemic findings may be associated with them. For example, cutaneous lesions of palpable purpura in a patient with LE are not lupus-specific, that is, such lesions may be seen in patients who do not have LE; however, they may be associated with vasculitic lesions of the kidney or central nervous system (CNS), and thus they have significance in the evaluation and treatment of lupus.
Table 22-1. Classification of Cutaneous Disease in Lupus Erythematosus
| LUPUS-SPECIFIC ERUPTIONS | LUPUS-NONSPECIFIC ERUPTIONS |
|---|---|
(Discoid lupus erythematosus (DLE), hypertrophic DLE, tumid LE, chilblain LE, lupus mucinotic nodules) |
2. What is acute cutaneous lupus erythematosus (ACLE)?
ACLE presents as an acute malar or more generalized photodistributed eruption. The malar erythema has been described as a “butterfly rash,” since the pattern across the cheeks resembles the wings of a butterfly (Fig. 22-1). Nearly all patients presenting with ACLE will have systemic lupus erythematosus (SLE), often in an acute flare. ACLE is usually transient, improving when the SLE improves, and generally does not result in scarring of the skin. A common diagnostic pitfall is the confusion of rosacea with the malar rash of ACLE. Rosacea is common; it is photo-exacerbated. Nonspecific joint symptoms are common, and 5% of the normal population will have a positive antinuclear antibody (ANA) test, often leading to a misdiagnosis of ACLE. Remember, a patient with ACLE is most often in an acute flare and will be “sick,” whereas a rosacea patient will have a chronic history and no systemic symptoms beyond their baseline “aches and pains.”
3. Are there any common skin eruptions that may be confused with acute cutaneous lupus erythematosus?
Many patients have complaints of erythema of the face due to a wide variety of conditions, but not all of them are photoinduced. The differential diagnosis of photosensitive eruptions of the face is not as broad and includes polymorphous light eruption, photoreactions to systemic medications and topical products, and certain types of porphyria (see Chapter 17). In addition, certain facial eruptions, such as rosacea, occasionally may be triggered or worsened by sun exposure. ACLE is an important cutaneous finding since it is strongly associated with SLE. Thus, patients with ACLE will have additional systemic complaints relating to SLE and will nearly always have a positive ANA test.
4. What is subacute cutaneous lupus erythematosus (SCLE)?
This type of cutaneous LE was first described and characterized in the late 1970s. These patients have an eruption that is more persistent than that of ACLE, lasting weeks to months or longer. The lesions of SCLE consist of scaly, superficial, inflammatory macules, patches, papules, and plaques that are photodistributed, particularly on the upper chest and back, lateral neck, and dorsal arms and forearms. Several different morphologic types of SCLE have been described: annular, serpiginous, and two types of papulosquamous lesions, psoriasiform and pityriasiform (Fig. 22-2). Some patients have more than one morphologic type of lesion.
Figure 22-1. Acute cutaneous lupus erythematosus. Note the classic malar erythema (“butterfly rash”).
5. Do patients with SCLE have SLE?
About one half of patients with SCLE will have four or more criteria for the classification of SLE, though most SCLE patients do not have serious renal or CNS lupus erythematosus. Typically, they have skin disease, photosensitivity, and musculoskeletal complaints. Dry eyes and dry mouth are also common. Some patients with SCLE experience severe manifestations of SLE, and thus all SCLE patients should be monitored for systemic disease.
6. How do you make a diagnosis of SCLE?
SCLE is a clinical diagnosis based on the presence of a typical photodistributed eruption and a skin biopsy consistent with cutaneous LE. Direct immunofluorescence testing may also be helpful. In addition to granular deposition of immunoreactants at the dermal–epidermal junction, particulate deposition of IgG within the epidermis has been described in SCLE. Most patients with SCLE have circulating antibodies to Ro/SS-A (Sjögren’s syndrome A) and, less commonly, to La/SS-B (Sjögren’s syndrome B). These antibodies are not demonstrable in all patients with SCLE; thus, their absence does not exclude this diagnosis. Additionally, a negative ANA does not exclude the diagnosis of SCLE, and some patients may have positive titers to Ro/SS-A or La/SS-B but test negative for ANA.
7. What is the initial workup of SCLE?
Once a diagnosis of SCLE is made, it is important to evaluate for the presence of SLE:
• History and physical examination data should be gathered to identify manifestations of SLE in other organ systems.
• Laboratory testing should be directed by findings on the history and physical exam but will generally include a complete blood count with differential, urinalysis, serum chemistries including renal function tests, and an ANA panel to include anti–Ro/SS-A, anti–La/SS-B, and anti–native DNA antibodies. Complement determinations may be ordered since some SCLE patients have partial or complete complement deficiencies.
• A medication history is very important since SCLE may be triggered or worsened by a number of medications, especially thiazide diuretics (Table 22-2). Some physicians recommend avoiding estrogens and sulfonamides in any patient with LE.
8. How is SCLE managed?
Cutaneous complaints are often of most concern to these patients, and thus dermatologists are generally the physicians managing this disease. Broad-spectrum sunscreens and sun-protective measures, including lifestyle changes and clothing, are perhaps the most important initial measures. Some patients respond to topical steroids, although potent topical steroids are usually required. Oral antimalarial therapy is also beneficial in many patients. Less commonly used treatments include dapsone, gold, immunosuppressive drugs, retinoids, and systemic steroids.
9. What is chronic cutaneous lupus erythematosus?
There are several types of cutaneous LE that are very persistent, termed chronic cutaneous lupus erythematosus. Discoid lupus erythematosus (DLE) is the most common of these chronic forms of cutaneous LE. An unusual variant of DLE with thick keratotic scale is referred to as hypertrophic DLE. Tumid LE is a variant where scale and other epidermal changes are absent. Lupus panniculitis and lupus mucinotic nodules are other forms of chronic cutaneous LE.
10. Describe the skin changes of discoid lupus erythematosus.
DLE is a chronic inflammatory disease consisting of fixed, indurated, erythematous papules and plaques that are often distributed on the head and neck, although any cutaneous region can be affected (Fig. 22-3
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