Development of bullous systemic lupus erythematosus in patient treated with NB-UVB: A case report and comprehensive review of the literature.

Bullous systemic lupus erythematosus (BSLE) is a rare form of cutaneous lupus erythematosus that presents as vesicles and blisters on various parts of the body. The pathological appearance of these lesions often shows subepidermal vesicles with deposits of IgG, IgM, IgA, and complement C3 in granular or linear forms under direct immunofluorescence (DIF) examination. Clinical studies demonstrate the effectiveness of phototherapy in treating various skin conditions. While several studies suggest a correlation between phototherapy and the development of vesiculobullous lesions, most of these reports are related to bullous pemphigoid, with limited research on the occurrence of BSLE following phototherapy. In this case report, vesicular and blistering lesions in a 70-year-old man undergoing UVB treatment for psoriasis are described. Pathological examination confirmed the diagnosis of bullous systemic lupus erythematosus, and the patient experienced significant improvement after treatment with dapsone tablets. A literature review was conducted on the development of vesiculobullous lesions after phototherapy, comparing different approaches presented in previous studies. Our conclusion highlights the importance of considering BSLE as a possible diagnosis in cases of vesiculobullous lesions post-phototherapy, alongside other potential conditions.