- Lupus is a disease that presents across a broad spectrum of cutaneous and systemic manifestations. It may be cutaneous-only or systemic with cutaneous manifestations; some patients with systemic lupus do not have cutaneous involvement. Diagnostic evaluation of a patient with lupus should be aimed at understanding which form of lupus the patient has; the specific diagnosis should inform appropriate treatment.
- Since the faces of patients with the classic facial eruption of systemic lupus erythematosus usually clear with treatment of their systemic disease, only the management of more common forms of cutaneous lupus will be discussed here. The four forms of cutaneous lupus discussed are: discoid lupus, subacute cutaneous lupus, lupus profundus, and bullous lupus.
- Subcutaneous lupus may be drug-induced in etiology.
Clinically, the cutaneous presentation of systemic lupus erythematosus (SLE) may have specific or non-specific features. Specific cutaneous signs include malar (butterfly) facial rash, discoid skin lesions, oral ulcers, and photosensitivity, especially in combination with systemic symptoms. Non-specific skin signs of systemic lupus include chilblains (pernio), livedo reticularis, vasculitis, and other (non-oral) ulcerations.
Cutaneous lupus erythematosus (CLE) may be divided into four subtypes: discoid lupus, subacute cutaneous lupus, lupus profundus, and bullous lupus. These subtypes can usually be distinguished by characteristic cutaneous features (see Table 1). Of note, these specific forms of cutaneous lupus may also occur in association with systemic lupus erythematosus. It is also important to note that some patients with cutaneous-only lupus may meet criteria for systemic lupus erythematosus.
The diagnosis of cutaneous lupus may be confirmed by skin biopsy, which in general reveals a vacuolar interface dermatitis, often in association with a lymphocytic infiltrate with plasma cells, epidermal atrophy, and mucin. Variants exist, such as bullous lupus, which is marked by the presence of bullous lesions clinically and histologically, the infiltrate of which may be comprised of neutrophils rather than lymphocytes. Lupus profundus has less epidermal and interface involvement, with the focus of inflammation in the subcutaneous fat. A direct immunofluorescence testing of the skin biopsy will reveal characteristic patterns, depending on the form of cutaneous lupus.
The goal of treatment for cutaneous lupus is directed at inflammation of the skin, and often requires systemic therapy. Prevention of cutaneous flares is essential, and avoidance of sun exposure and any exacerbating medications are key elements. Medications associated with subacute cutaneous lupus include: anti-fungal medications (terbinafine more commonly than griseofulvin), hydrochlorothiazide, calcium channel blockers, angiotensin-converting enzyme inhibitors, beta-blockers, interferons, anticonvulsants (carbamazepine, phenytoin), glyburide, penicillamine, spironolactone, statins, psoralen, sulfonylurea, NSAIDs (piroxicam, naproxen), diltiazem, biologics (etanercept, efalizumab), antihistamines (ranitidine), and chemotherapy (docetaxel). Stopping the triggering medication will lead to resolution, but only over several months.
Table 1. Subtypes of cutaneous lupus
|Sub-type||Characteristic features of cutaneous presentation||Notes|
|Discoid lupus||Photosensitive, annular plaques with central scarring (hypopigmented or depigmented) rimmed with peripheral hyperpigmentation Common involvement of scalp, face, conchal bowl of ear, neck||Heal with pigmentary changes, scarring and alopecia (if scalp involvement is present) Rare cases progress to systemic lupus erythematosus Patients with systemic lupus erythematosus may have discoid lesions|
|Subacute cutaneous lupus||Photosensitive, papulosquamous eruption or annular violaceous to erythematous scaly plaques||80% ANA+ Many patients are also Ro/SSA+ May be drug-induced|
|Lupus profundus||Minimal epidermal change Subcutaneous warmth, nodules, and/or atrophy||Cheeks, chest, shoulders, hips, buttocks, face Disfiguring|
|Bullous lupus||Bullous lesions, often photosensitive|
|Neonatal lupus||Violaceous to erythematous scaly plaques, often with periocular involvement (raccoon eyes)||Female patients (newborns) Anti-Ro/SSA (87%)+ Anti-La/SSB (50%)+ Born to mothers who are Ro/SSA+ but may be asymptomatic Association with congenital heart block in up to 50% patients, also cardiomyopathy|