Bullae for you: The increasing importance and implications of drug-induced bullous pemphigoid

Atypical Bullous Pemphigoid After Linagliptin Intake

BACKGROUND Bullous pemphigoid is a common pruritic skin lesion reported in elderly patients. It is caused by an immunologic reaction between autoantibodies and hemidesmosome proteins of epithelial cells. The disease is characterized by a symmetrical blister distribution on the body. Diagnosis should be suspected in elderly patients presenting with a tense blister on normal-appearing skin or on an erythematous base. In the literature, several forms of typical bullous pemphigoid after treatment with linagliptin have been reported. However, this is the first reported case of atypical nonbullous pemphigoid after linagliptin intake. CASE REPORT A 77-year-old woman presented with multiple erythematous papules and nodules on the upper extremities and trunk. The patient was being treated with linagliptin for diabetes. Diagnosis was made with biopsy and histopathological studies, followed by direct immunofluorescence. The histopathological study showed a subepidermal blister with an underlying polymorphous infiltrate, mainly of an eosinophilic profile. Direct immunofluorescence showed linear IgG and C3 antibodies to hemidesmosomes at the lamina lucida of the basement membrane. Thus, the diagnosis of atypical nonbullous pemphigoid was made. CONCLUSIONS This report emphasizes the great variety of bullous pemphigoid presentation and the need for a greater level of awareness of the adverse effects of linagliptin. Thus, atypical nonbullous pemphigoid should be considered among the potential differential diagnoses in patients with multiple erythematous papules and nodules on the upper extremities and trunk.

Cutaneous immune-related adverse events to checkpoint inhibitors

The development of immunotherapy has led to a paradigm shift in the treatment of both solid and hematologic malignancies. As immunomodulatory therapies are employed with increasing frequency, a greater number of immune-related adverse reactions are being reported, and the majority of these involve the skin. As a result, dermatologists are increasingly becoming involved in the management of these cutaneous adverse reactions-often providing critical recommendations regarding ongoing cancer treatment. Cutaneous immune-related adverse reactions can vary significantly from patient to patient, making early recognition and timely intervention imperative to mitigate associated morbidity and potential treatment interruption. Although there is considerable overlap in the cutaneous adverse events caused by these immune checkpoint inhibitors, specific eruptions are characteristically associated with particular checkpoint inhibitors. In addition, a patient's comorbidities or immune status can play a significant role in the presentation and management of such adverse reactions. This review characterizes and provides management guidelines for the various cutaneous toxicities associated with checkpoint inhibitor therapy, including CTLA-4 inhibitors, PD-1 inhibitors, and PD-L1 inhibitors. © 2020 Elsevier Inc. All rights reserved.

The pathogenesis of bullous skin diseases

Bullous skin diseases are a group of dermatoses characterized by blisters and bullae in the skin and mucous membranes. The etiology and pathogenesis of bullous skin diseases are not completely clear. The most common are pemphigus and bullous pemphigoid (BP). Autoantibodies play critical roles in their pathogenesis. Abnormalities in the adhesion between keratinocytes in patients with pemphigus leads to acantholysis and formation of intra-epidermal blisters. Anti-desmoglein autoantibodies are present both in the circulation and skin lesions of patients with pemphigus. The deficient adhesion of keratinocytes to the basement membrane in BP patients gives rise to subepidermal blisters. Autoantibodies against the components of hemidesmosome can be detected in BP patients. Many novel therapeutics based on knowledge of the pathogenesis have emerged in recent years.

Bullous pemphigoid induced by dipeptidyl peptidase-4 (DPP-4) inhibitors: a pharmacovigilance-pharmacodynamic/pharmacokinetic assessment through an analysis of the vigibase®

Objectives: To examine the signals of bullous pemphigoid (BP) with dipeptidyl peptidase-4 inhibitors (DPP-4i) in VigiBase® and the potential role of their pharmacodynamic/pharmacokinetic parameters in the occurrence of BP. Methods: Case/non-case analyses were performed in VigiBase® to examine the signal of BP [reporting odds ratio (ROR)] for gliptins. Secondly, the authors performed linear regression analyses to explore the association between DPP-4i signals for BP and their affinities toward different target enzymes (DPP-2, DPP-4, DPP-8, and DPP-9) and their volume of distribution (Vd). Results: A significant BP signal was found for DPP-4i. The ROR for pooled DPP-4i was 179.48 (95% CI: 166.41-193.58). The highest ROR was found for teneligliptin 975.04 (801.70-1185.87) and lowest for saxagliptin 18.9 (11.5-30.9). Linear regression analyses showed a considerable trend to significance for the linear correlation between the BP signal and gliptin affinity at DPP-4 (slope = 1.316 [-0.4385-3.21], p = 0.067, R² = 0.40) but not the other enzyme targets, nor for Vd. Conclusion: The findings suggest a clinical relevance of gliptins selectivity for DDP-4 in the development of BP as a result of exposure to these drugs. Future preclinical and clinical studies are needed for a better understanding of this correlation.