Current Concepts of Dermatitis Herpetiformis

Allergenic Biomarkers in the Molecular Diagnosis of IgE-Mediated Wheat Allergy

IgE-mediated wheat allergy can take on various forms, including childhood food allergy to wheat, wheat-dependent exercise-induced anaphylaxis in young adults, baker's respiratory allergy/asthma in workers exposed to wheat flour inhalation, and contact urticaria that is caused by hydrolyzed wheat proteins in some cosmetics, and that is sometimes associated with a food allergy. Singleplex and multiplex immunoassays detect specific IgE antibodies to wheat allergenic molecular biomarkers such as omega-5 gliadin Tri a 19, lipid transfer protein Tri a 14, and alpha-amylase inhibitors. The fluorescence enzyme immunoassay with capsulated cellulose polymer solid-phase coupled allergens is a commonly used singleplex assay. Multiplex methods include the ELISA-based macroarray immunoassay using nano-bead technology and a microarray immunoassay on polymer-coated slides. Another promising diagnostic tool is the basophil activation test performed with omega-5 gliadin and other wheat protein types. Detailed comprehension of the structural and immunological features of the numerous wheat allergens significant in clinical settings is imperative for advancing diagnostic biomarkers for IgE-mediated wheat allergies.

Improving the Diagnosis of Dermatitis Herpetiformis Using the Intraepithelial Lymphogram

Dermatitis herpetiformis is a cutaneous manifestation of celiac disease. Phenotyping of intraepithelial lymphocytes in the small bowel mucosa can strengthen the diagnosis of celiac disease when it is not clear-cut. We aim to evaluate the usefulness of the intraepithelial lymphogram to confirm dermatitis herpetiformis in equivocal cases. We performed a retrospective multicenter study on patients diagnosed with dermatitis herpetiformis and collected data from the intraepithelial lymphogram assessed by flow cytometry. A total of 36 patients were analyzed in relation to the severity of intestinal damage (18 had non-atrophic mucosa) at baseline (N = 28) and/or after the adoption of a gluten-free diet (median follow-up of three years, N = 16). We observed that patients with atrophy more often had positive celiac serology (p = 0.019), celiac clinical symptoms (p = 0.018), and iron-deficiency anemia (p = 0.018), but the severity of skin damage was similar in both groups (p = 0.79). At baseline, increased TCRγδ+ cells were present in 94% of patients with atrophy and 67% with non-atrophic lesions (p = 0.13). After a gluten-free diet, increased TCRγδ+ cells persisted in 100% and 63% of cases, respectively (p = 0.21). We concluded that increased TCRγδ+ cells may be helpful in confirming the diagnosis of dermatitis herpetiformis in equivocal cases, even in patients who were started on a gluten-free diet.

Patient-reported burden of skin disorders in coeliac disease

OBJECTIVES

The current knowledge on the associations between coeliac disease and different skin diseases is contradictory and the patient's perspective on the burden of these is lacking. This study aimed to investigate patient-reported frequency, severity and quality of life effects of skin disorders in coeliac disease patients compared to controls and moreover to study the impacts of gluten-free diet on these skin diseases.

MATERIALS AND METHODS

A study questionnaire designed for the purposes of this study and a validated Dermatology Life Quality Index (DLQI) questionnaire were posted to 600 adult members of the Finnish Coeliac Society and 1173 matched controls. Responses from 327 coeliac disease patients and 382 non-coeliac controls were compared.

RESULTS

Coeliac disease patients were shown to be at no increased risk of atopic dermatitis, acne, rosacea, psoriasis, alopecia areata, vitiligo or chronic urticaria. The severity of these skin diseases did not differ between study groups, but the risk for at least moderate effects on quality of life caused by dermatological diseases was increased among those with coeliac disease. Positive response from gluten-free diet was most commonly experienced by coeliac disease patients with atopic dermatitis.

CONCLUSIONS

Even though the risk for skin diseases was shown not to be increased among coeliac disease patients, there is still an increased burden related to experienced skin symptoms among these patients, which non-dermatologists treating coeliac disease patients should acknowledge.

Skin gluten-related disorders: new and old cutaneous manifestations to be considered

The term gluten-related disorders (GRD) refer to a spectrum of different clinical manifestations triggered by the ingestion of gluten in genetically susceptible individuals, including coeliac disease (CD), wheat allergy and non-celiac gluten sensitivity (NCGS). GRD are characterized by a large variety of clinical presentations with both intestinal and extra-intestinal manifestations. The latter may affect almost every organ of the body, including the skin. Besides the well-known association between CD and dermatitis herpetiformis, considered as the cutaneous specific manifestation of CD, many other muco-cutaneous disorders have been associated to GRD. In this review, we analyzed the main features of dermatological diseases with a proven association with GRD and those that improve after a gluten-free diet, focusing on the newly described cutaneous manifestations associated with NCGS. Our main hypothesis is that a "cutaneous-gluten sensitivity," as specific cutaneous manifestation of NCGS, may exist and could represent a diagnostic marker of NCGS.

Classification and Antigen Molecules of Autoimmune Bullous Diseases

Autoimmune bullous diseases (AIBDs), which are a group of tissue-specific autoimmune diseases of the skin, present with various blistering lesions on the skin and mucous membranes, and show autoantibodies of IgG, IgA and IgM against epidermal cell surfaces and basement membrane zone. To date, AIBDs have been classified into a number of distinct subtypes by clinical and histopathological findings, and immunological characteristics. In addition, various biochemical and molecular biological studies have identified various novel autoantigens in AIBDs, which has resulted in proposals of new subtypes of AIBDs. In this article, we summarized various distinct AIBDs, and proposed the latest and most comprehensive classification of AIBDs with their autoantigen molecules.

Urticaria: A Narrative Overview of Differential Diagnosis

Urticaria is an inflammatory skin disorder that may occur in isolation or associated with angioedema and/or anaphylaxis. Clinically, it is characterized by the presence of smooth, erythematous or blanching, itchy swelling, called wheals or hives, which greatly vary in size and shape and last less than 24 h before fading to leave normal skin. Urticaria is the consequence of mast-cell degranulation that can be caused by immunological or non-immunological mechanisms. From a clinical point of view, many skin conditions can mimic urticaria and their recognition is mandatory for a correct management and therapeutic approach. We have reviewed all of the main relevant studies which addressed differential diagnosis of urticarial, published until December 2022. The National Library of Medicine PubMed database was used for the electronic research. The present review offers a clinical narrative overview, based on the available literature, of the principal skin disorders that can be misdiagnosed as urticaria (mainly autoinflammatory or autoimmune disorders, drug-induced reactions, and hyperproliferative diseases). The aim of this review is to provide clinicians a useful tool for correctly suspecting and identifying all of these conditions.

Immunopathological Assessment of the Oral Mucosa in Dermatitis Herpetiformis

Dermatitis herpetiformis (Duhring's disease, DH) is a chronic blistering cutaneous condition with pruritic polymorphic lesions, consisting of vesicles, papules or nodules and erythema, found predominantly on the extensor surfaces of the limbs, buttocks, and neck. Diagnosis is based on characteristic clinical and immunopathological findings. Oral manifestations of DH have rarely been described. The aim of the study was to evaluate IgA, IgG, IgM and C3 complement deposits in the oral mucosa in DH patients. Direct immunofluorescence (DIF) was performed on the oral mucosa specimens collected from 10 DH patients. Biopsy was taken in a local anesthesia from perilesional site from the buccal mucosa and then preserved in a standard procedure using polyclonal rabbit IgG, IgA, IgM and C3 antibodies. Granular IgA and C3 deposits were found in 6 patients (60%), and in 3 subjects (30%) the result was indeterminate. Significant fluorescence of the deposits along the basement membrane was observed in 2 patients, moderate fluorescence in 3 patients, and in 4 cases the result was indeterminate. C3 deposits were found in 5 subjects (50%), 3 of them being moderate and 2 indeterminate. No IgM and IgG deposits were detected in the collected buccal mucosa specimens.

Prevalence of celiac disease in patients with liver diseases: a systematic review and meta-analyses

OBJECTIVES

A subset of patients with celiac disease (CeD) have liver involvement in the form of hypertransaminasemia, liver cirrhosis and autoimmune hepatitis. We conducted a systematic review with meta-analyses to determine pooled prevalence of CeD in patients with cryptogenic cirrhosis, all-cause cirrhosis, cryptogenic hypertransaminasemia, and all-cause hypertransaminasemia.

METHODS

We searched PubMed and EMBASE up to January 2022. Cross-sectional, case-control and prospective cohort studies performing serological tests and/or intestinal biopsy for CeD on patients with cryptogenic cirrhosis, all-cause cirrhosis, cryptogenic hypertransaminasemia and all-cause hypertransaminasemia were included, to calculate pooled estimates of seroprevalence and prevalence of biopsy-confirmed CeD in these four groups.

RESULTS

Of 6,871 articles screened, 20 articles were included finally in three meta-analyses for cryptogenic cirrhosis, all-cause cirrhosis and cryptogenic hypertransaminasemia. For the all-cause hypertransaminasemia group, a qualitative review of four studies was done instead of a meta-analysis, due to significant differences in studies. The pooled prevalence (95%CI) of biopsy-confirmed CeD, in cryptogenic cirrhosis was 4.6%(2.2-7.5%) while pooled prevalence of biopsy-confirmed CeD in all-cause cirrhosis was 0.8%(0-3.4%). Pooled prevalence of biopsy-confirmed CeD in cryptogenic hypertransaminasemia was 5.7%(3.2-8.8%).

CONCLUSIONS

Nearly one in 20 patients each with cryptogenic cirrhosis and cryptogenic hypertransaminasemia have CeD, hence they should both be considered high-risk groups for CeD. While prevalence of CeD in all-cause cirrhosis is similar to that in general population, it may be worth screening them for CeD as liver pathology has potential for reversal in them.

The risk of renal comorbidities in celiac disease patients depends on the phenotype of celiac disease

BACKGROUND

An increased risk of kidney disease in patients with celiac disease has been reported, but the association has remained obscure. Only few studies have investigated the association between renal comorbidities and dermatitis herpetiformis, a cutaneous manifestation of celiac disease.

OBJECTIVES

We investigated whether patients with different phenotypes of celiac disease are at higher risk of kidney diseases than age- and sex-matched references.

METHODS

The diagnoses of glomerulonephritis, diabetic nephropathy, interstitial nephritis, and end-stage renal disease obtained from the National Hospital Discharge Register between 1970 and 2015 were identified in celiac disease (Marsh III, n = 1072) and dermatitis herpetiformis (n = 368) patients diagnosed at Tampere University Hospital catchment region and in 4296 reference subjects. Using the Cox proportional hazards model, we compared the risk of kidney diseases between patients and references. The study protocol was approved by the Regional Ethics Committee of Tampere University Hospital (R16090). As the study was register based, no consent from patients was required.

RESULTS

Even after adjusting for type 1 diabetes, celiac disease was associated with an elevated risk of kidney disease (hazard ratio [HR] 1.85, 95% confidence interval [CI] 1.12-3.03), glomerulonephritis (HR 3.37, 95% CI 1.64-6.95), and IgA nephropathy (IgAN) (HR 18.98, 95% CI 2.29-157.63). No similarly elevated risk was found among dermatitis herpetiformis patients (HR 1.50, 95% CI 0.63-3.55; HR 2.21, 95% CI 0.77-6.38; and HR 5.87, 95% CI 0.53-64.79, respectively).

CONCLUSION

Celiac disease patients were at increased risk of kidney diseases, notably IgAN. The risk was dependent on the celiac disease phenotype and was not seen in patients with dermatitis herpetiformis. Awareness of possible renal manifestations is recommended when treating celiac disease patients.

Histopathology of autoimmune bullous dermatoses: What's new?

Autoimmune bullous dermatoses are characterized by the presence of tissue-bound and often circulating pathogenic autoantibodies targeting structural components of the skin and/or mucous membranes. The diagnostic workup for this heterogeneous group of disorders consists of a multi-step process, of which the light microscopic examination is a crucial component. This review is organized following a classification scheme that is based on two main histopathologic features, namely level of intraepithelial split and composition of the inflammatory infiltrate. Overall, we aim to place emphasis on the histopathologic clues that can assist pathologists in differential diagnosis and review the updates in the literature.

Sex-differences in Gluten-free Dietary Adherence and Clinical Symptoms in Patients with Long-term Treated Dermatitis Herpetiformis

Dermatitis herpetiformis is a blistering autoimmune skin disease, and a cutaneous manifestation of coeliac disease. The burden of coeliac disease is increased especially in females, but studies concerning sex differences in patients with long-term treated dermatitis herpetiformis are scarce. This questionnaire study compared adherence to a gluten-free diet, clinical symptoms and well-being between females and males in a cohort of 237 long-term treated (median 24 years) patients with dermatitis herpetiformis. Females had better adherence to a gluten-free diet (p = 0.022) and they used dapsone significantly less often at the time of the study than did males (4% vs 13%, p = 0.017). The occurrence of skin symptoms was equal in both sexes, but dermatological quality of life was lower in females (p = 0.024), and gastrointestinal symptoms were more severe among females with dermatitis herpetiformis than among males (p = 0.027). In conclusion, long-term treated female patients with dermatitis herpetiformis have better adherence to a gluten-free diet, but they also experience more severe clinical symptoms compared with males.

Super-resolution imaging detects BP180 autoantigen in immunoglobulin M pemphigoid

Bullous pemphigoid is generally caused by immunoglobulin (Ig)G autoantibodies against hemidesmosomal BP180 and/or BP230. Recently, the concept of IgM pemphigoid has been proposed. A 23-year-old Japanese woman presented with a 4-month history of severely itchy papules showing subepidermal separations with mild neutrophil infiltration. Direct immunofluorescence (DIF) revealed IgM deposits at the dermoepidermal junction, but neither IgG nor IgA deposits. Indirect immunofluorescence on 1 M NaCl-split skin demonstrated deposits on the epidermal side. The optical density (OD) value of a modified IgM enzyme-linked immunosorbent assay for full-length BP180, but not for BP180-NC16A, was increased. The patient was diagnosed with IgM pemphigoid and was treated with diphenyl sulfone at 50 mg/day without recurrence. To confirm the precise autoantigen, we tried to obtain super-resolution imaging. The deposition pattern of IgM autoantibodies seemed to be oriented parallel to that of BP180. The detailed images detect DIF deposits apart from BP180-NC16A staining, but are close to type VII collagen-NC1 staining. This result suggests that the IgM autoantibodies in the patient might target the C-terminus of BP180. IgM pemphigoid is still not a widely accepted concept, and the clinical course remains unknown. We will carefully follow-up the patient. Super-resolution images may help to detect precise autoantigens in autoimmune blistering diseases.

THE MANAGEMENT OF DERMATITIS HERPETIFORMIS BY THE GASTROENTEROLOGIST. A SERIES OF CASES

BACKGROUND

Dermatitis herpetiformis (DH) is considered a skin celiac disease (CD). The individuals can be seen by primary care professionals or by dermatologists that could refer the patient to a gastroenterologist.

OBJECTIVE

The study aimed to investigate the clinical profile of patients diagnosed with DH and referred to a gastroenterologist and evaluate the treatment response.

METHODS

We retrospectively studied patients with DH referred to the same gastroenterologist at a private office in Curitiba, Brazil, between January 2010 to December 2019. We included adult patients with a confirmed DH diagnosis. Symptoms, clinical signs, laboratory and histological data, as well as treatment response, were collected.

RESULTS

Thirty-three patients were studied (60.6% women, mean age at diagnosis 40.8±12.61 years). The median delay for DH diagnosis was four years. Skin involvement was mild in 33.3%, moderate in 18.2%, and severe in 48.5%. The more frequent gastrointestinal complaints were abdominal distension (78.8%), flatulence (75.7%), and gastroesophageal reflux (51.5%). Depression and anxiety were observed in 81.8% and anemia in 51.1%. A higher prevalence of bone disorders was associated with higher age at DH diagnosis (P=0.035). Duodenal biopsy showed changes in all patients. Improvement after treatment only with a gluten-free diet (GFD) plus dapsone was verified in 81.2%.

CONCLUSION

Patients with DH referred to a gastroenterologist showed a high frequency of gluten intolerance and systemic complaints. Duodenal histological alterations were found in all the cases. The treatment based on GFD plus dapsone was effective in most patients.

Celiac disease in the COVID-19 pandemic

Background

The COVID-19 pandemic has had an impact on global health.

Design

The impact of the COVID-19 pandemic on patients with coeliac disease was assessed in the present review.

Results

The incidence of coeliac disease and the problems associated with coeliac disease increased during the COVID-19 pandemic. Adherence to the diet is crucial for the patient's health and quality of life since the only approved therapy for coeliac disease is a gluten withdrawal.

Conclusions

A gluten-free diet should be promoted by the therapeutic team and implemented among these categories of patients.

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Health education to follow the GFD does not exist in many countries. Unfortunately, the COVID-19 pandemic has increased psychological problems among patients with CD.

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The association of T1D with CD has been and remains a problem in CD management.

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Associating IBD with CD is again a challenge. Psychological problems also appeared in the associations of CD with T1D and IBD. The COVID-19 virus did not pose an increased risk to CD patients, but the COVID-19 pandemic brought many psychological problems to CD patients.

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CD patients should adhere to GFD, in general, hence pay attention to gluten withdrawal during the COVID-19 pandemics, to avoid other complications and improve their QOL.

Clinical Application of Pharmacogenetic Markers in the Treatment of Dermatologic Pathologies

Dermatologic pathologies are the fourth most common cause of non-fatal disease worldwide; however, they produce a psychosocial, economic, and occupational impact equal to or greater than other chronic conditions. The most prevalent are actinic keratosis, followed by basal-cell carcinoma, in a lesser proportion acne vulgaris, psoriasis, and hidradenitis suppurativa, among others, and more rarely dermatitis herpetiformis. To treat actinic keratosis and basal-cell carcinoma, 5-fluorouracil (5-FU) 0.5% is administered topically with good results, although in certain patients it produces severe toxicity. On the other hand, dapsone is a drug commonly used in inflammatory skin conditions such as dermatitis herpetiformis; however, it occasionally causes hemolytic anemia. Additionally, biologic drugs indicated for the treatment of moderate-to-severe psoriasis and hidradenitis suppurativa have proved to be effective and safe; nevertheless, a small percentage of patients do not respond to treatment with biologics in the long term or they are ineffective. This interindividual variability in response may be due to alterations in genes that encode proteins involved in the pathologic environment of the disease or the mechanism of action of the medication. Pharmacogenetics studies the relationship between genetic variations and drug response, which is useful for the early identification of non-responsive patients and those with a higher risk of developing toxicity upon treatment. This review describes the pharmacogenetic recommendations with the strongest evidence at present for the treatments used in dermatology, highlighting those included in clinical practice guides. Currently, we could only find pharmacogenetic clinical guidelines for 5-FU. However, the summary of product characteristics for dapsone contains a pharmacogenetic recommendation from the United States Food and Drug Administration. Finally, there is an enormous amount of information from pharmacogenetic studies in patients with dermatologic pathologies (mainly psoriasis) treated with biologic therapies, but they need to be validated in order to be included in clinical practice guides.

Dermatitis Herpetiformis: An Update on Diagnosis, Disease Monitoring, and Management

Dermatitis herpetiformis (DH), Duhring disease, is caused by gluten sensitivity and affects 11.2 to 75.3 per 100,000 people in the United States and Europe with an incidence of 0.4 to 3.5 per 100,000 people per year. DH is characterized by a symmetrical blistering rash on the extensor surfaces with severe pruritus. The diagnosis continues to be made primarily by pathognomonic findings on histopathology, especially direct immunofluorescence (DIF). Recently, anti-epidermal transglutaminase (TG3) antibodies have shown to be a primary diagnostic serology, while anti-tissue transglutaminase (TG2) and other autoantibodies may be used to support the diagnosis and for disease monitoring. Newly diagnosed patients with DH should be screened and assessed for associated diseases and complications. A gluten-free diet (GFD) and dapsone are still mainstays of treatment, but other medications may be necessary for recalcitrant cases. Well-controlled DH patients, managed by a dermatologist, a gastroenterologist, and a dietician, have an excellent prognosis. Our review comprehensively details the current diagnostic methods, as well as methods used to monitor its disease course. We also describe both the traditional and novel management options reported in the literature.

Educational Case: Dermatitis Herpetiformis

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, see http://journals.sagepub.com/doi/10.1177/2374289517715040.1.

Autoantibodies Against the Immunodominant Bullous Pemphigoid Epitopes Are Rare in Patients With Dermatitis Herpetiformis and Coeliac Disease

Dermatitis herpetiformis (DH) is an extraintestinal manifestation of coeliac disease (CD). Patients with DH have an elevated risk of development of another autoimmune blistering skin disease, bullous pemphigoid (BP). In this study we investigated whether patients with DH and CD (mean age for both 49 years) have circulating autoantibodies against BP180, the major BP autoantigen. ELISA tests showed that only a few DH (3/46) and CD (2/43) patients had BP180-NC16A IgG autoantibodies. Immunoblotting found that more than half of the DH samples contained IgG autoantibodies against full-length BP180. Epitope mapping with 13 fusion proteins covering the BP180 polypeptide revealed that in DH and CD patients, IgG autoantibodies did not target the NC16A or other epitopes typical of BP but recognized other intracellular and mid-extracellular regions of BP180. None of the analyzed DH and CD patients with either ELISA or immunoblotting positivity had IgG or IgA reactivity against the cutaneous basement membrane in indirect immunofluorescence analysis or skin symptoms characteristic of BP. Although only a minority of middle-aged DH patients had IgG autoantibodies against the immunodominant epitopes of BP180, our results do not exclude the possibility that intermolecular epitope spreading could explain the switch from DH to BP in elderly patients.