Bullous lesions in SLE-A Diagnostic Dilemma!

An 18-year-old female presented with painful bullous skin lesions over the abdomen of 1-week duration. She was diagnosed as a case of systemic lupus erythematosus (SLE) with proliferative lupus nephritis, a month back, and treated with high-dose steroids and currently on monthly cyclophosphamide pulse therapy. She denies any new drug intake in the last 2 weeks. On clinical examination, there were multiple erythematous vesiculobullous lesions over the anterior abdomen [Figure 1a]. Her investigations revealed mild anemia, normal acute phase reactants, but low complement level (C3 – 60 mg/dL, C4 – 4.5 mg/dL). Patient being on high-grade immunosuppression, we kept infectious etiology, specifically herpes zoster, as the first differential diagnosis, but Lupus-related (LE) vesiculobullous lesions were also considered. She underwent a biopsy of the skin lesion, which revealed subepidermal large bullae with few neutrophils. Dermis underneath bullae showed multiple neutrophilic abscess [Figure 1c and d]. Direct immunofluorescence (DIF) showed linear deposits of immunoglobulin G along the basement membrane. Based on clinical findings and histopathology, she was diagnosed as a case of bullous systemic lupus erythematosus (BSLE) started on dapsone 50 mg twice a day after a G6PD assay. She showed remarkable improvement with the complete disappearance of skin lesions after 2 weeks of therapy [Figure 1b]. We highlight a rare and challenging case of SLE with vesiculobullous lesions.Figure 1: (a) Multiple erythematous vesiculobullous lesions over the abdomen (b) Complete healing of lesions after 2 weeks of dapsone therapy (c and d) Histopathology showing subepidermal bullae and neutrophilic microabscess in the dermis, suggestive of bullous lupusBullous lesions in SLE can be directly related to lupus or unrelated causes like herpes zoster due to high-dose immunosuppression. Bullous lesions in lupus can be classified into LE-specific, LE-aspecific vesiculobullous diseases, LE-related autoimmune bullous diseases, and LE association to nonautoimmune conditions.[1] LE-associated bullous lesions can range from minor forms to life-threatening conditions like Toxic Epidermal Necrolysis like presentation requiring prompt immunosuppressive therapy.[2] BSLE is a lupus-aspecific vesiculobullous occurs rarely in patients with SLE. It may or may not correspond to the exacerbation of systemic disease.[3] Classical histopathological findings are subepidermal blistering, predominance of neutrophils in the upper dermis with deposition of immune complexes on DIF. Dapsone is the initial choice of therapy.[4] Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initials will not be published and due efforts will be made to conceal her identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.