BSLE is often an acute onset presentation with tense vesicles and bullae over erythematous or normal skin. These blisters appear more in sun-exposed areas but can be seen in non-sun-exposed skin and mucosa with a predilection for the trunk, face, neck, vermillion border, upper extremities-extensor surfaces, supraclavicular region, and oral mucosa.[4][11]

A rare pattern, erythema gyratum repens described as a centrifugally migrating erythematous plaque, has been described.[12][13]

BSLE may be associated with urticarial lesions, and pruritus is not always present. Healing with milia and/or scarring occurs infrequently. However, hypo/hyperpigmentation of the affected skin is usually seen.[8]

Several reports have shown an association with BSLE and active lupus nephritis. A multi-center retrospective study and literature review with a total of 128 cases described lupus nephritis in 50% of the cases, mainly class III or IV. 7% of cases had neuropsychiatric SLE and 45% with hematologic involvement at the time of BSLE.[8]

A careful review of the clinical presentation, serologies, histology, and immunofluorescence are required in the process of diagnosis.

In 1983 Camisa and Sharma proposed the following diagnostic criteria for BSLE which was later revised in 1986:[14][15]

• A diagnosis of SLE based on the American College of Rheumatology (ACR) criteria
• Vesicles and bullae arising upon but not limited to sun-exposed skin
• Histopathology compatible with dermatitis herpetiformis (DH)
• Negative or positive indirect immunofluorescence (IIF) for circulating BMZ autoantibodies
• Direct immunofluorescence (DIF) revealing IgG and/or IgM and often IgA at the BMZ

In 1995, Yell et all described BSLE as "an acquired subepidermal blistering disease in a patient with SLE with immune reactants at the BMZ on either DIF or IIF".[11]

Detection of an autoantibody directed against collagen VII was shown to play a role in BSLE. The criteria by Camisa and Sharma were made before the availability of ELISA or immunoblot technology. The use of ELISA for detecting antibodies against NC1 and NC2 of type VII collagen is utilized.[16]

However, it is important to note that a diagnosis of SLE is usually present however, this may be a first presentation of SLE in a few cases. A thorough exclusion of other blistering diseases should also be completed.

Dapsone is considered the first line of treatment with a good response.[17]

The use of dapsone, however, may have a few side effects including but not limited to anemia, hepatitis, or hypersensitivity syndrome. In the event of intolerance, systemic manifestation, or extensive skin involvement, the use of steroids may be considered.

Several steroid-sparing agents have been used in the literature with variable efficacy. These immunosuppressive medications include cyclophosphamide, azathioprine, mycophenolate mofetil, methotrexate, with modest results. Rituximab has shown some promise with refractory cases.

Less infrequently, anakinra and intravenous immunoglobulins have been reported.[8]

BSLE may be confused with several other blistering diseases, especially two autoimmune blistering conditions: dermatitis herpetiformis (DH), or epidermolysis bullosa acquisita (EBA).

Epidermolysis bullosa acquisita (EBA) exhibits similar antibodies against type VII collagen. It is more likely to heal with scarring and milia formation compared to BSLE. A prominent distinguishing feature includes the absence of SLE and a lack of histologic finding of large deposits of mucin in the dermis. The poor or slow response to dapsone in EBA compared to BSLE may help in separating the two entities.

Dermatitis herpetiformis (DH) has a skin distribution different from BSLE. The pruritic lesions have a predilection to the extensor surfaces, elbows, knees, and buttocks. DH is histologically identical to BSLE except for the presence of IgA deposition within the dermal papilla.[18]

Other differential diagnoses include:

• Linear IgA bullous dermatosis: immunofluorescence shows IgA deposition on the epidermal side of split skin
• Systemic lupus erythematosus with blisters
• Bullous pemphigoid: With the aid of immunofluorescence antibody deposition is found on the epidermal side of salt-split skin

In a 12-year retrospective review, the majority of the patients healed without scarring or milia, although post-inflammatory hypo- or hyper-pigmentation may be seen. It was also pointed out that BSLE rarely recurred.[19]

Complications include:

• Infection of exposed and affected skin
• Sloughing esophagitis
• Complications from concomitant multi-organ SLE flare
• Medication side effects

Patient education is very vital in the management of BSLE. For a few, this may present as the first manifestation of SLE, which is a chronic, autoimmune condition with several multi-organ involvements. Educate these patients on the early signs and symptoms of organ involvement, photoprotection with sunscreen, and the need for medication adherence.

BSLE poses significant stress related to discomfort, aesthetics, and concern of skin complications. Support groups and behavioral therapy may be needed in such cases.

A multidisciplinary approach in evaluation, treatment, and care of patients with BSLE cannot be over-emphasized.

Primary care physicians, rheumatologists, and dermatologists play a key role in early diagnosis. The histopathology mimics of BSLE can be a source of a wrong diagnosis and delay of treatment, thus the need for an experienced pathologist.

Skincare by trained and dedicated nurses of the skin lesions, especially when ruptured leaving behind crusts and erosions, is also important.

Clinicians, nurses, and pharmacists also need to educate their patients on the disease condition, medications, and their potential side effects.

In cases with concomitant lupus nephritis, neuropsychiatric lupus, and hematologic complications, other subspecialties such as nephrology, neurology, and hematology may be needed.

Most importantly, the patient and family need to be involved in the treatment strategies, especially on decisions to escalate treatment to immunosuppressants. [Level V]