The association of bullous pemphigoid (BP) with the use of dipeptidylpeptidase 4 (DPP-4) inhibitors among patients with diabetes has recently emerged. The risk of developing BP during treatment with new DPP-4 inhibitor agents like linagliptin is yet to be established. The clinical features and the prognostic outcomes of patients with DPP-4 inhibitor-associated BP are yet to be established. OBJECTIVES Primarily to estimate the association between DPP-4 inhibitor exposure and the development of BP, and secondarily to characterize the clinical features and history of patients with DPP-4 inhibitor-associated BP. DESIGN, SETTING, AND PARTICIPANTS A retrospective case-control study of the intake of different DPP-4 inhibitor agents and metformin and occurrence of BP among patients with diabetes in a tertiary care referral center for autoimmune bullous diseases in northern Israel. Included were 82 consecutive patients with diabetes and immunopathologically validated BP diagnosed between January 1, 2011, and December 31, 2017, and 328 age-, sex-, and ethnicity-matched control participants with diabetes but without BP. MAIN OUTCOMES AND MEASURES Patients with diabetes and BP and exposure to DPP-4 inhibitors were followed up for a median of 2.0 years and compared with other patients with diabetes and BP who were not exposed to DPP-4 inhibitors regarding clinical and immunological features, laboratory analyses, treatments, and clinical outcomes. RESULTS Eighty-two patients with BP and 328 age-and sex-matched control participants were enrolled; mean (SD) age, 79.1 (9.1) years; and 44 patients were female (53.7%). Overall, DPP-4 inhibitor intake was associated with a 3-fold increased risk for BP (adjusted odds ratio [OR], 3.2; 95% CI, 1.9-5.4). The adjusted ORs for vildagliptin and linagliptin were 10.7 (95% CI, 5.1-22.4) and 6.7 (95% CI, 2.2-19.7), respectively. The association of DPP-4 inhibitor use with BP was independent of the use of metformin and was stronger among male (OR, 4.46; 95% CI, 2.11-9.40) than female (OR, 1.88; 95%, CI 0.92-3.86) patients and strongest in patients younger than 70 years (OR, 5.59; 95% CI, 1.73-18.01). Patients with DPP-4 inhibitorassociated BP presented with higher mucosal involvement (22.2% vs 6.5%; P = .04) and lower mean (SD) peripheral eosinophil counts (399.8 [508.0] vs 1117.6 [1847.6] cells/μL; P = .01) than those with BP who had not been exposed to DPP-4 inhibitor. Discontinuation of DPP-4 inhibitor treatment was followed by improved clinical outcomes. CONCLUSIONS AND RELEVANCE Vildagliptin and, to a lesser extent, linagliptin are associated with an increased risk of BP. This may partly explain the increasing incidence of BP in Israel. Discontinuation of DPP-4 inhibitor treatment in patients with diabetes should be considered when BP is diagnosed.

Pemphigus forms a group of rare autoimmune bullous diseases that affect the skin and mucous membranes. This group has a chronic course leading to high morbidity and mortality. It is characterized by the production of pathogenic autoantibodies directed against different proteins of the desmosome, leading histologically to intraepidermal cleavage, and clinically to vesicles and erosions on the epithelium of the mucous membranes and/or the skin. The diagnosis of the subtype of pemphigus is based on clinical features, the level of histologic cleavage, and the identification of the antigens recognized by circulating autoantibodies by immunoserological analyses. The epidemiological features of pemphigus vary considerably in different regions of the world. Observational studies examining comorbidities and associations among patients with pemphigus are scarce and sometimes inconclusive. The prognosis, mortality, and clinical outcomes in pemphigus have undergone dramatic change throughout the years. This review provides a brief overview about the different subtypes of pemphigus: pemphigus vulgaris, pemphigus foliaceus, paraneoplastic pemphigus, pemphigus herpetiformis, and IgA pemphigus. In addition, it summarizes the most recent understanding of the epidemiology, mortality data, and comorbidities of this group of organ-specific autoimmune diseases.

Bullous pemphigoid (BP) is the most common type of subepidermal autoimmune bullous diseases. BP characteristically affects the elderly and is seen mainly in patients older than 70 years. While the annual incidence of BP has been estimated to be between 2.4 and 23 cases per million in the general population, it rises exponentially to 190–312 cases per million in individuals older than 80 years. In addition, a growing body of evidence reports a remarkable trend of increased incidence of BP, showing a 1.9- to 4.3-fold rise over the past two decades. This demonstrable increase warrants a higher awareness of the increased risk to develop BP. This review summarizes the current understanding of the epidemiological features of BP and sheds light on the putative explanations for its growing incidence.

Bullous pemphigoid (BP) is an autoimmune blistering disease which carries a significant mortality and morbidity. While historically BP has been characterized as an IgG driven disease mediated by anti-BP180 and BP230 IgG autoantibodies, developments in recent years have further elucidated the role of eosinophils and IgE autoantibodies. In fact, eosinophil infiltration and eosinophilic spongiosis are prominent features in BP. Several observations support a pathogenic role of eosinophils in BP: IL-5, eotaxin, and eosinophil-colony stimulating factor are present in blister fluid; eosinophils line the dermo-epidermal junction (DEJ) in the presence of BP serum, metalloprotease-9 is released by eosinophils at the site of blisters; eosinophil degranulation proteins are found on the affected basement membrane zone as well as in serum corresponding with clinical disease; eosinophil extracellular DNA traps directed against the basement membrane zone are present, IL-5 activated eosinophils cause separation of the DEJ in the presence of BP serum; and eosinophils are the necessary cell required to drive anti-BP180 IgE mediated skin blistering. Still, it is likely that eosinophils contribute to the pathogenesis of BP in numerous other ways that have yet to be explored based on the known biology of eosinophils. We herein will review the role of eosinophils in BP and provide a framework for understanding eosinophil pathogenic mechanisms in mucocutaneous disease.

Pemphigus vulgaris (PV) is a life-threatening disease belonging to the pemphigus group of autoimmune intra-epidermal bullous diseases of the skin and mucosae. The therapeutic management of PV remains challenging and, in some cases, conventional therapy is not adequate to induce clinical remission. The cornerstone of PV treatment remains systemic corticosteroids. Although very effective, long-term corticosteroid administration is characterized by substantial adverse effects. Corticosteroid-sparing adjuvant therapies have been employed in the treatment of PV, aiming to reduce the necessary cumulative dose of corticosteroids. Specifically, immunosuppressive agents such as azathioprine and mycophenolate mofetil are widely used in PV. More recently, high-dose intravenous immunoglobulins, immunoadsorption, and rituximab have been established as additional successful therapeutic options. This review covers both conventional and emerging therapies in PV. In addition, it sheds light on potential future treatment strategies for this disease.

Little is known about differences in epidemiological features and prognosis between pemphigus vulgaris (PV) and pemphigus foliaceus (PF). The objective of this study was to compare PV and PF patients regarding ethnic variations and mortality rates. Mortality of PV and PF patients was compared with age- and sex-matched control subjects in the general population. The study cohort comprised 207 patients with PV and 30 with PF diagnosed during the period 2000 to 2015. The incidence rate of PV among Jews was 3.6-fold higher than among Arabs (p<0.001), whereas no ethnic predisposition to PF was noted (p = 0.379). The risk of death for patients with PV was almost 3-fold higher than in the general population (standardized mortality ratio (SMR) 2.6). For patients with PF, the risk of mortality was not significantly increased relative to the general population (SMR 1.4). There is a racial predisposition to PV, whereas PF is sporadic. Mortality among patients with PV is higher compared with PF and the general population.

Subepidermal autoimmune bullous diseases of the skin and mucosae comprise a large group of chronic diseases, including bullous pemphigoid, pemphigoid gestationis, mucous membrane pemphigoid, linear IgA bullous dermatosis, epidermolysis bullosa acquisita, and anti-p200 pemphigoid. These diseases are characterized by an antibody response toward structural components of the basement membrane zone, resulting in subepidermal blistering. The epidemiological features of these diseases vary substantially in different regions of the world. Observational studies investigating comorbidities and associations among patients with these diseases are inconsistent and sometimes inconclusive. This review provides a brief overview regarding each one of the subepidermal autoimmune bullous diseases. In addition, it summarizes the most recent understanding of the epidemiological features and associations of this group of organ-specific autoimmune diseases.

ost patients with bullous pemphigoid (BP) classically present with tense blisters and erythema, seen predominantly in the limb flexures and the abdomen, and often in conjunction with urticarial plaques. Meanwhile, 20% present with atypical manifestations, including prurigo-like type, 1 urticaria-like type, 2 eczema-like type, 3 and dyshidrosiform type. 4 Involvement of the mucous membranes was considered an atypical physical feature by the clinical criteria of Vaillant et al, 5 which yields a positive predictive value of 95% for a clinical diagnosis of BP. Mucosal lesions in BP are typically restricted to the oral mucosa and may be observed in up to 20% of patients. [6][7][8] The involvement of other mucosal surfaces is less established and based on anecdotal case reports. [9][10][11][12][13] To our knowledge, the frequency of nonoral mucosal involvement among patients with BP was not evaluated previously in the setting of cohort or large case series studies. The knowledge about the precise mucosal structures that may be affected in BP and of the distinct features of patients with BP who have mucosal involvement is very limited.The objectives of the current study were to evaluate the prevalence of general mucosal involvement in patients with BP and to characterize the subgroup of patients with mucosal lesions, using a large cohort of patients with welldefined and immunopathologically validated BP. IMPORTANCE The prevalence of mucosal involvement in bullous pemphigoid (BP) is inconsistent. Nonoral mucosal involvement was reported anecdotally in few patients with BP.OBJECTIVE To evaluate the prevalence of mucosal involvement in patients with BP, and to characterize the subgroup of patients with mucosal lesions. DESIGN, SETTING, AND PARTICIPANTSA retrospective cohort study was performed including 328 consecutive patients diagnosed with immunopathologically validated BP at a tertiary care referral center for autoimmune bullous diseases in northern Israel between January 1, 2000, and December 31, 2017. MAIN OUTCOME AND MEASURESThe study was conducted to estimate the prevalence and distribution of mucosal involvement among patients with BP. Patients with mucosal involvement were compared with the remaining BP patients regarding clinical and immunological features, laboratory analyses, and treatments. RESULTSThe study cohort included 139 (42.4%) male and 189 (57.6%) female patients, with a mean (SD) age of 78.0 (11.8) years at presentation. Fifty-six patients (17.1%) presented with mucosal lesions. The oral mucosa was the most frequently affected mucosal surface (n = 44; 13.7%), followed by the laryngeal (n = 16; 4.9%) and the genital (n = 10; 3.0%) mucosae. Among patients with oral lesions, the most involved oral structures were the buccal mucosa (n = 25; 55.6%) and the soft palate (n = 24; 53.3%). Compared with other patients with BP, patients with mucosal involvement were younger (71.8 [14.4] years vs 79.3 [10.8] years; P < .001), presented more frequently with extensive disease (55.4% vs 39.7%; P = .002), had less p...