Challenges and pitfalls between lichen planus pemphigoides and bullous lichen planus

Autoimmune bullous dermatoses in cancer patients treated by immunotherapy: a literature review and Italian multicentric experience

Cutaneous immune-related adverse events are frequently associated with immune checkpoint inhibitors (ICIs) administration in cancer patients. In fact, these monoclonal antibodies bind the cytotoxic T-lymphocyte antigen-4 and programmed cell death-1/ligand 1 leading to a non-specific activation of the immune system against both tumoral cells and self-antigens. The skin is the most frequently affected organ system appearing involved especially by inflammatory manifestations such as maculopapular, lichenoid, psoriatic, and eczematous eruptions. Although less common, ICI-induced autoimmune blistering diseases have also been reported, with an estimated overall incidence of less than 5%. Bullous pemphigoid-like eruption is the predominant phenotype, while lichen planus pemphigoides, pemphigus vulgaris, and mucous membrane pemphigoid have been described anecdotally. Overall, they have a wide range of clinical presentations and often overlap with each other leading to a delayed diagnosis. Achieving adequate control of skin toxicity in these cases often requires immunosuppressive systemic therapies and/or interruption of ICI treatment, presenting a therapeutic challenge in the context of cancer management. In this study, we present a case series from Italy based on a multicenter, retrospective, observational study, which included 45 patients treated with ICIs who developed ICI-induced bullous pemphigoid. In addition, we performed a comprehensive review to identify the cases reported in the literature on ICI-induced autoimmune bullous diseases. Several theories seeking their underlying pathogenesis have been reported and this work aims to better understand what is known so far on this issue.

Case report: Successful treatment of non-bullous lichen planus pemphigoides with dupilumab

Lichen planus pemphigoides (LPP) is a rare autoimmune bullous disease, characterized by the coexistence of lichen planus and subepidermal bullae. However, the minority of LPP patients present with papules rather than vesicles or blisters, which is defined as non-bullous LPP. The diagnosis of LPP relies on manifestations, histopathology, serological assay, and direct immunofluorescence of linear disposition of IgG and/or C3 at the basement membrane zone. Up to now, no standard therapeutic strategies have been proposed for the treatment of LPP. Herein, we describe an uncommon non-bullous LPP patient with widespread papules and erythema, probably induced by vaccination. During hospitalization, he had a poor response to the conventional treatment of topical and systemic corticosteroids, and his condition was finally alleviated by the addition of dupilumab. For LPP patients with a traditional medication failure, or who were not suitable for a higher dose of corticosteroids, a combination with dupilumab could be an alternative option.

Effective treatment of refractory lichen planus pemphigoides with a Janus kinase-1/2 inhibitor

Lichen planus pemphigoides is a rare autoimmune subepidermal blistering disease clinically and histopathologically characterized by features of lichen planus and bullous pemphigoid. We describe a case of refractory lichen planus pemphigoides successfully treated with the selective and reversible Janus kinase-1/2 inhibitor, baricitinib.