The global incidence of bullous pemphigoid: a systematic review and meta-analysis

BACKGROUND

Bullous pemphigoid (BP) is an autoimmune blistering disorder that mainly affects older people. Although the disease is associated with considerable morbidity and mortality, the burden of disease worldwide is unclear.

OBJECTIVES

The study aim is to pool the global incidence of BP and determine whether this varies according to geographic area, age group, setting and study quality.

METHODS

Ovid MEDLINE, Ovid Embase and grey literature were systematically searched on 7 April 2020. Two reviewers independently screened, extracted data and appraised each study's quality using the Joanna Briggs Institute critical appraisal tool. Two domains, indicative of selection and survey bias, were used to identify high-quality studies. The cumulative incidence was standardized to 1 year and pooled in a random-effects meta-analysis. Subgroup and sensitivity analyses were conducted.

RESULTS

Twenty-seven studies were identified, of which 23 provided cumulative incidence and four provided incidence rates. The cumulative incidence of BP was 8·2 [95% confidence interval (CI) 4·8-13.7] per million people whereas the incidence rate was 34·2 (95% CI 19·2-60·7) per million person-years. Of the continents that contributed more than one study, the cumulative incidence was 10·3 (95% CI 5·8-18·2) and 5·6 (95% CI 3·5-9·0) per million people in Europe and Asia, respectively. The incidence was highest in studies including adults only (n = 2), in population-based studies (n = 9) and in more recent years. The cumulative incidence was higher (13·3 per million people, 95% CI 6·0-29·5) when restricting the analysis to higher-quality studies (n = 11). High heterogeneity (I² > 82%) was observed across all pooled estimates.

CONCLUSIONS

The incidence of BP varies globally, is generally low but appears to be increasing over time. The burden of disease is likely to be underestimated.

Toxic epidermal necrolysis-like lupus

Toxic epidermal necrosis (TEN)-like lupus is a rare condition characterized by epidermal loss and mucosal ulceration occurring in patients with acute severe flares of systemic lupus erythematosus. The clinical picture may mimic drug-induced Stevens-Johnson syndrome/TEN; however, the absence of a suitable culprit drug, and the context of acute lupus point to the correct diagnosis. In a case series of three patients, further discriminating features included a slower onset of epidermal loss, more limited mucosal ulceration and a lack of ocular involvement when compared with drug-induced TEN. Histology may show similar features, including basal layer vacuolation, apoptosis and full-thickness epidermal necrosis. Patients with TEN-like lupus may have additional features of lupus, and a lupus band on direct immunofluorescence. It is important to identify this condition correctly, so that these patients can be appropriately managed with early input from Rheumatologists and prompt treatment with high-dose combined immunosuppressant therapy.

Using electronic health records to inform trial feasibility in a rare autoimmune blistering skin disease in England

Background

Trials of novel agents are required to improve the care of patients with rare diseases, but trial feasibility may be uncertain due to concerns over insufficient patient numbers. We aimed to determine the size of the pool of potential participants in England 2015–2017 for trials in the autoimmune blistering skin disease bullous pemphigoid.

Methods

The size of the pool of potential participants was estimated using routinely collected healthcare data from linked primary care (Clinical Practice Research Datalink; CPRD) and secondary care (Hospital Episode Statistics; HES) databases. Thirteen consultant dermatologists were surveyed to determine the likelihood that a patient would be eligible for a trial based on the presence of cautions or contra-indications to prednisolone use. These criteria were applied to determine how they influenced the potential pool of participants.

Results

Extrapolated to the population of England, we would expect approximately 10,800 (point estimate 10,747; 95% CI 7191 to 17,239) new cases of bullous pemphigoid to be identified in a three-year period. For a future trial involving oral prednisolone (standard care), the application of cautions to its use as exclusion criteria would result in approximately 365 potential participants unlikely to be recruited, a further 5332 could be recruited with caution, and 5104 in whom recruitment is still possible. 11–17% of potential participants may have pre-existing dementia and require an alternative consent process.

Conclusions

Routinely collected electronic health records can be used to inform the feasibility of clinical trials in rare diseases, such as whether recruitment is feasible nationally and how long recruitment might take to meet recruitment targets. Future trials of bullous pemphigoid in England may use the data presented to inform trial design, including eligibility criteria and consent processes for enrolling people with dementia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-021-01212-1.

What's new in atopic eczema? An analysis of systematic reviews published in 2018. Part 1: prevention and topical therapies

This review is part of a series of annual updates that summarize the evidence base for atopic eczema (AE). The aim is to provide a succinct guide for clinicians on the key findings from 14 systematic reviews on the prevention and topical treatment of AE published or indexed in 2018. Various supplements, including long-chain polyunsaturated fatty acids, vitamin D and the probiotic Lactobacillus rhamnosus GG, given prenatally and postnatally, have not been shown to prevent AE in infants, although mixed strains of probiotics may decrease the risk of AE if given to the mother during pregnancy and to the infant for the first 6 months of life. In the postnatal period, there is no evidence that hydrolysed formula, compared with cow's milk formula (CMF), reduces the risk of AE in partially breastfed infants. However, weak evidence suggests that a specific partially hydrolysed whey formula decreases the risk of AE compared with CMF. No specific skin practices can be recommended to reduce the eczema risk in healthy term babies. There is weak evidence of a low risk of reversible hypothalamic-pituitary-adrenal axis suppression following 2-4 weeks of treatment with low-potency topical steroids, and conflicting evidence as to whether bleach bathing affects skin flora or AE severity. A single study demonstrated that the topical Janus kinase inhibitor tofacitinib at 2% significantly reduces the Eczema Area and Severity Index compared with vehicle. Topical naltrexone cream 1% improves pruritus (measured using a visual analogue scale) by 30% more than placebo. There is weak evidence that topical alternative therapies, including antioxidants, micronutrients and some herbal medicines, may improve AE.

Incidence, prevalence and mortality of bullous pemphigoid in England 1998-2017: a population-based cohort study

BACKGROUND

A rising incidence and high mortality were found for bullous pemphigoid (BP) over a decade ago in the UK. Updated estimates of its epidemiology are required to understand the healthcare needs of an ageing population.

OBJECTIVES

To determine the incidence, prevalence and mortality rates of BP in England from 1998 to 2017.

METHODS

We conducted a cohort study of longitudinal electronic health records using the Clinical Practice Research Datalink and linked Hospital Episode Statistics. Incidence was calculated per 100 000 person-years and annual point prevalence per 100 000 people. Multivariate analysis was used to determine incidence rate ratios by sociodemographic factors. Mortality was examined in an age-, sex- and practice-matched cohort, using linked Office of National Statistics death records. Hazard ratios (HRs) were stratified by matched set.

RESULTS

The incidence was 7·63 [95% confidence interval (CI) 7·35-7·93] per 100 000 person-years and rose with increasing age, particularly for elderly men. The annual increase in incidence was 0·9% (95% CI 0·2-1·7). The prevalence almost doubled over the observation period, reaching 47·99 (95% CI 43·09-53·46) per 100 000 people and 141·24 (95% CI 125·55-158·87) per 100 000 people over the age of 60 years. The risk of all-cause mortality was highest in the 2 years after diagnosis (HR 2·96; 95% CI 2·68-3·26) and remained raised thereafter (HR 1·54; 95% CI 1·36-1·74).

CONCLUSIONS

We report a modest increase in the incidence rate of BP, but show that the burden of disease in the elderly population is considerable. Mortality is high, particularly in the first 2 years after diagnosis.

What's new in atopic eczema? An analysis of systematic reviews published in 2017. Part 1: treatment and prevention

This review forms part of a series of annual updates that summarize the evidence base for atopic eczema (AE). It provides a summary of key findings from 25 systematic reviews that were published or indexed during 2017, and focuses on the treatment and prevention of AE. There is high-quality evidence to demonstrate that dupilumab is better than placebo for the treatment of AE, is not associated with a higher incidence of adverse effects and does not increase the risk of infection compared with placebo; however, comparison studies with other systemic treatments are necessary. Topical tofacitinib is a promising treatment for mild-moderate AE, but currently lacks sufficient evidence from well-designed randomized controlled trials (RCTs) comparing with other active treatments. Topical doxepin may be effective for pruritus in AE, but available studies have short follow-up periods and longer-term outcomes are needed. Bleach baths were no more effective than water baths alone at reducing AE severity. Topical antibiotics cannot be recommended for infected AE, owing to insufficient evidence of benefit. There is little comparison of different emollients in RCTs, but overall evidence indicates that they reduce AE severity, are steroid-sparing and lead to better outcomes in combination with topical corticosteroids (TCS) than TCS alone. No clear benefit was demonstrated for vitamin D/C/E supplementation in pregnancy for eczema prevention.

What's new in atopic eczema? An analysis of systematic reviews published in 2016. Part 3: nomenclature and outcome assessment

This review forms part of a series of annual updates that summarize the evidence base for atopic eczema (AE). It presents the key findings from 11 systematic reviews published in 2016 that focus on AE outcome assessment, disease impact and nomenclature. Systematic reviews on the treatment and prevention of AE are summarized in Part 1 of this update, and systematic reviews on the epidemiology of and risk factors for AE are summarized in Part 2. Six reviews summarized what outcome measurement instruments have been used in published AE trials, or summarized validation studies for the available instruments. These reviews were used to inform consensus decisions by the Harmonising Outcome Measures for Eczema initiative. Although validated instruments exist for clinical signs and patient-reported symptoms, there are currently no validated instruments for capturing quality of life or long-term control. Four reviews examined the impact of AE on children and their families, but few studies were included. One birth cohort study found no association between AE and educational attainment at 11 years. AE has a moderate impact on health-related quality of life and a substantial impact on family life. AE is a major risk factor for occupational hand dermatitis, and it is advised that young atopic individuals are informed about high-risk occupations. Further efforts are required to standardize the nomenclature for AE, which is also commonly known as 'atopic dermatitis' or 'eczema', and preferred terms vary around the world.

Generating new evidence, improving clinical practice and developing research capacity: the benefits of recruiting to the U.K. Dermatology Clinical Trials Network's STOP GAP and BLISTER trials

Clinical trials may benefit clinical practice in three ways: firstly, clinicians may change their practice according to the new trial evidence; secondly, clinical processes can improve when working on a trial; and thirdly, research capacity is increased. We held a meeting to present and discuss the results of two large multicentre randomized controlled trials delivered through the U.K. Dermatology Clinical Trials Network. Investigators gave reflections on how the trials had changed their clinical practice. The STOP GAP trial showed that prednisolone and ciclosporin are equally effective as first-line systemic treatment for pyoderma gangrenosum. The final decision of which treatment to use should be based on the different adverse event profiles of the two drugs in relation to comorbidities, along with age, disease severity and patient preference. The BLISTER trial showed that starting people with pemphigoid on doxycycline produces acceptable short-term effectiveness and a superior safety profile to oral corticosteroids. Recruiting to these trials has led to the development of new specialist clinics with improved documentation. It has increased the profile of participating departments and embedded research in the department's activities. Helping to design and run these trials has also allowed trial staff to develop new skills in research design, which has been beneficial for career development. These and other benefits of recruiting to the trials are summarized here. We hope that these reflections will inspire wider involvement in clinical research.

Positron emission tomography features of hidradenitis suppurativa

A 35-year-old male with classical Hodgkin's lymphoma (nodular sclerosing, grade 1 histology, clinical stage 2A) underwent a positron emission tomography (PET) scan to assess response to treatment. Half body CT PET imaging was obtained using a Siemens Biograph scanner from eyes to thighs. 405 MBq of 18-fluorodeoxyglucose (FDG) was injected with acquisition starting at 60 min. There was unexpected intense focal uptake in the superficial subcutaneous tissues of the abdomen, pelvis and lateral chest wall with overlying skin thickening seen on the CT component. This was initially of concern, but the patient was known to have a history of hidradenitis suppurativa (HS). On further examination, the radiological abnormalities corresponded to the clinical sites of involvement. To the best of our knowledge, this is the first documentation of the appearance of HS on PET scan.

Blistering skin disorders: an evidence-based update. Conference report

Evidence-based update meetings are held annually by the Centre of Evidence Based Dermatology, University of Nottingham. Past topics have included important themes such as eczema, psoriasis, hair disorders and skin cancers. This year, the seventh Evidence Based Update meeting focused on blistering disorders and took place in Loughborough University on 5 June 2008. The latest data on incidence and mortality, therapeutic trials and management of bullous pemphigoid, pemphigus and epidermolysis bullosa (EB) were presented by an international panel of renowned speakers. The highlights of the meeting included an informal atmosphere, an international perspective, a practical question and answer session and hearing first-hand a patient and carer's perspective of living with EB.

Acute generalized exanthematous pustulosis associated with azathioprine hypersensitivity

Acute generalized exanthematous pustulosis (AGEP) is identified by several characteristic features. We present a patient showing AGEP associated with azathioprine hypersensitivity. To our knowledge, this is the first reported case of this association.

Acquired haemophilia heralded by bleeding into the oral mucosa in a patient with bullous pemphigoid, rheumatoid arthritis, and vitiligo

Acquired haemophilia is rare and potentially fatal, with a mortality of 20% if left untreated. There is a strong association with other autoimmune diseases. This report describes a patient with rheumatoid arthritis, vitiligo, and bullous pemphigoid where the diagnosis of acquired haemophilia was made after an extensive bleed into a bullous lesion in the buccal mucosa. This case highlights some of the potential complications of acquired haemophilia and its treatment.

Evidence of an association between desmoglein 3 haplotypes and pemphigus vulgaris

BACKGROUND

Pemphigus vulgaris (PV, OMIM 169610) is a severe blistering disorder of the skin and mucous membranes, caused by the production of autoantibodies directed against the epithelial adhesive protein desmoglein 3. Although an association between PV and HLA class II alleles has been established, the genetic factors predisposing to the disease remain poorly understood, the rarity of PV hampering the recruitment of substantial patient cohorts.

OBJECTIVES

To investigate DSG3 as a candidate PV susceptibility gene.

METHODS

We examined five DSG3 single nucleotide polymorphisms (rs8085532, rs3911655, rs3848485, rs3794925 and rs1466379) in two case-control datasets respectively originating from the U.K. (62 PV patients, 154 controls) and northern India (28 patients, 98 controls).

RESULTS

In the U.K. sample, we observed a significant association between PV and the DSG3*TCCTC haplotype (Fisher's exact test P = 0.002). A related haplotype (DSG3*TCCCC) was associated with PV in the Indian dataset (P = 0.002). We also found that all British and Indian patients bearing DSG3 risk haplotypes carried at least one copy of a PV-associated HLA allele.

CONCLUSIONS

These results suggest that genetic variation of DSG3 may be an additive risk factor predisposing to PV and warrant further investigations of this gene.

Trends in the presentation of cutaneous malignant melanoma over three decades at King's College Hospital, London

The aim of this study was to examine trends in the presentation of cutaneous malignant melanoma at King's College Hospital (KCH) over the last three decades (1970-2000). KCH was one of seven centres that participated in the 1987 Cancer Research Campaign (CRC) publicity campaign aimed at promoting earlier self-recognition of melanoma. Data included patient age at presentation, sex, tumour site, Breslow thickness and histological subtype. The late 1980s saw a threefold increase in the annual number of melanomas and an eightfold increase in thin melanomas compared to the 1970s. The increase occurred in both sexes and was particularly marked after the CRC campaign but numbers had already begun to increase prior to this. The increase has predominantly been thin (Breslow < 1.5 mm) tumours of the superficial spreading variety with a resultant fall in mean Breslow thickness. There has been a decline in the annual number of melanomas since the peak in 1992 which is not explained by increased proportion of in situ tumours. The CRC campaign may have contributed to the documented increase in thin tumours but this trend had begun prior to 1987 suggesting factors other than public awareness and earlier presentation are important. It is encouraging that the number of melanomas has declined over the last 5 years at KCH but it is yet to be seen whether this reflects a real decrease in the incidence of melanoma.

Guidelines

These guidelines for management of pemphigus vulgaris have been prepared for dermatologists on behalf of the British Association of Dermatologists. They present evidence-based guidance for treatment, with identification of the strength of evidence available at the time of preparation of the guidelines, and a brief overview of epidemiological aspects, diagnosis and investigation.

Persistent anticonvulsant hypersensitivity syndrome responding to ciclosporin

The drug hypersensitivity syndrome is a severe, multisystem reaction that typically develops within 2 months of starting a drug. We describe a case which has been unusually persistent, requiring prolonged treatment with systemic corticosteroids and after 1 year, ciclosporin. To the best of our knowledge, the use of ciclosporin for the treatment of the drug hypersensitivity syndrome has not been described previously.

An evaluation of the usefulness of mycophenolate mofetil in pemphigus

BACKGROUND

Pemphigus is a group of autoimmune blistering diseases of the skin and/or mucous membranes requiring management with immunosuppressive therapy. The optimal therapeutic regimen would rapidly induce remission and maintain effectiveness with minimal adverse effects in the long term.

OBJECTIVES

The present study describes our experience of the addition of mycophenolate mofetil (MMF) to prednisolone in the management of severe, refractory pemphigus.

METHODS

Patients with active, refractory pemphigus were treated with MMF. Our series included 12 cases of pemphigus vulgaris, four cases of pemphigus foliaceous and one case of paraneoplastic pemphigus. All patients were monitored to assess disease control and mycophenolate toxicity.

RESULTS

Of the 17 cases, MMF has been of benefit to 12. MMF was well tolerated and there were no treatment withdrawals because of safety concerns.

CONCLUSIONS

We found that MMF permitted a reduction in prednisolone dosage without disease relapse.

Psoriasis bullosa acquisita

We report a 51-year-old man with a 20-year history of chronic plaque psoriasis who developed an autoimmune subepidermal blistering eruption that had clinical features of bullous pemphigoid, erythema multiforme and epidermolysis bullosa acquisita. Investigations revealed a 1 : 400 titre circulating and in vivo bound IgG autoantibody that mapped to the dermal side of 1 m NaCl-split skin and localized to the lower lamina lucida/upper lamina densa on immunogold electron microscopy. Immunoblotting, using dermal extracts, showed serum binding to antigens of approximately 200- and approximately 260 kDa. Indirect immunofluorescence microscopy, using the patient's serum on archival skin sections taken from selected individuals with different forms of inherited epidermolysis bullosa as substrate, showed normal basement membrane labelling on all samples apart from recessive dystrophic epidermolysis bullosa skin (with inherent mutations in the type VII collagen gene): in these cases there was a complete absence of immunostaining. Clinically, the patient responded rapidly to combination treatment with intravenous immunoglobulin and oral corticosteroids, dapsone and mycophenolate mofetil. Autoimmune subepidermal blistering has been reported in other patients with psoriasis, although no specific target antigen has ever been determined. Our study provides preliminary evidence that, for this patient at least, the autoantibody may be targeted against a skin component closely associated with type VII collagen (the epidermolysis bullosa acquisita antigen). Therefore, we propose the term 'psoriasis bullosa acquisita' for this and possibly other patients with similar skin eruptions.

New laboratory techniques for the assessment of acquired immunobullous disorders

This review aims to summarize investigations that are used in the assessment of patients with suspected immunobullous disorders. Emphasis is placed upon new adaptations of existing techniques and the advent of recombinant technology, which has enabled the production of synthetic antigens. The use of recombinant antigens has provided the latest generation of diagnostic techniques that are likely to make a major impact on routine diagnosis of immunobullous disorders.

The severity of cutaneous and oral pemphigus is related to desmoglein 1 and 3 antibody levels

BACKGROUND

Pemphigus vulgaris (PV) and foliaceus (PF) are characterized by antibodies to the desmosomal proteins desmoglein 3 (Dsg3) and desmoglein 1 (Dsg1), respectively. Past studies using indirect immunofluorescence (IIF) as a measure of pemphigus antibody levels have failed to demonstrate consistently a relationship between disease severity and IIF titres. However, IIF is not able to measure separately Dsg1 and 3 antibodies, unlike enzyme-linked immunosorbent assays (ELISA), which utilize recombinant proteins.

OBJECTIVES

To compare independently Dsg1 and 3 antibody levels with the severity of both cutaneous and oral involvement in PV and PF. Patients and methods Four hundred and twenty-four serum samples were analysed from 80 subjects with PV and 24 with PF. IgG antibodies to Dsg1 and 3 were measured by ELISA. For every sample analysed, the associated severity of skin and oral disease were graded from 0 to 3; quiescent, mild, moderate and severe.

RESULTS

A relationship between Dsg1 antibodies and skin severity was demonstrated such that a 10-unit increase in Dsg1 ELISA value was associated with a 34% chance of having a higher severity score [95% confidence interval (CI), 25-45%, P < 0.0005]. This was observed in both PV and PF. Oral severity was associated with Dsg3 antibody levels and a 10-unit increase in the Dsg3 ELISA value was associated with a 25% chance of a higher oral severity score (CI 17-33%, P < 0.0005). We were unable to demonstrate a relationship between Dsg1 antibodies and oral severity, even after adjusting for the effect of Dsg3 antibodies. Similarly, there was no relationship between Dsg3 antibodies and skin severity.

CONCLUSIONS

This study suggests that the clinical phenotype of pemphigus, in particular the balance of skin and oral disease, is determined principally by the quantities of Dsg1 and 3 autoantibodies, respectively.

A study of desmoglein 1 autoantibodies in pemphigus vulgaris: racial differences in frequency and the association with a more severe phenotype

BACKGROUND

Pemphigus vulgaris (PV) is characterized by pathogenic autoantibodies to desmoglein (Dsg) 3, but additional antibodies to Dsg1, the pemphigus foliaceus antigen, are detectable in some cases.

OBJECTIVES

To investigate the clinical significance of the presence of both Dsg 1 and 3 antibodies.

METHODS

In 79 subjects with PV, enzyme-linked immunosorbent assays were used to detect IgG autoantibodies reactive with the ectodomain of Dsg1 and Dsg3.

RESULTS

There was a clear association between the clinical phenotype and the Dsg antibody profile. All subjects had Dsg3 autoantibodies and 61% had coexisting Dsg1 antibodies (Dsg3+/Dsg1+). PV limited entirely to the mucosal surfaces was seen only in Dsg3+/Dsg1- patients, while additional Dsg1 antibodies (Dsg3+/Dsg1+) predicted cutaneous in addition to mucosal involvement. Although minor cutaneous involvement was observed in most Dsg3+/Dsg1- patients, severe cutaneous involvement was seen only in Dsg3+/Dsg1+ patients. Dsg1 antibodies were detectable early in the course of disease and their appearance did not relate to the use of systemic therapy. The proportion of Dsg1+ patients was higher in those of Indian origin compared with white northern Europeans (P < 0.05).

CONCLUSIONS

These data suggest that the presence of Dsg1 antibodies is predictive of a potentially more severe disease and that genetic factors may determine the Dsg antibody profile.