類天疱瘡（後天性表皮水疱症を含む。）

BACKGROUND: Considerable uncertainty exists regarding the prevalence and clinical significance of basement membrane zone (BMZ) anti-IgE antibodies in bullous pemphigoid (BP). OBJECTIVE: To assess the frequency of linear BMZ anti-IgE antibody deposition by direct immunofluorescence (DIF) and evaluate its association with disease severity and potential diagnostic utility in BP. METHODS: This prospective cross-sectional analytical study enrolled 50 patients with newly diagnosed BP, confirmed by DIF and serology, and 50 non-BP controls. Associations with clinical disease severity and laboratory parameters were analysed. An exploratory diagnostic performance analysis of anti-IgE positivity was also performed. RESULTS: The mean age of the study and control populations was 65.1 ± 17 and 58.2 ± 18.5 years, respectively. BMZ anti-IgE antibodies were detected in 27/50 BP patients (54%) and 1/50 (2%) controls [odds ratio (OR) 57.5, 95% confidence interval (CI), 7.4-449.7; p < 0.001]. Anti-IgE positivity was significantly associated with bullous pemphigoid disease area index (BPDAI) total and BPDAI-Erosion-Blister scores, total body surface area, high absolute eosinophil count (AEC), and increased serum IgE. In multivariate logistic regression, elevated AEC and increased serum IgE independently predicted anti-IgE positivity [adjusted-OR (95% CI): 1.004 (1.000-1.008); p = 0.037 and 1.003 (1.000-1.005); p = 0.033, respectively]. Anti-IgE positivity demonstrated 54% sensitivity, 98% specificity and a positive likelihood ratio of 27. CONCLUSIONS: BMZ anti-IgE antibody was present in over half of the patients with BP and was associated with greater disease severity, eosinophilia and elevated serum IgE. Given its high specificity but modest sensitivity, anti-IgE positivity may serve as a useful adjunctive marker to support, rather than exclude, the diagnosis of BP.

Mucous membrane pemphigoid is a rare autoimmune blistering disease that may involve multiple mucosal sites and is often diagnosed after substantial delay. We retrospectively reviewed 23 patients with mucous membrane pemphigoid seen at Toyama University Hospital between January 2016 and January 2026 to characterize their clinical and immunopathological features, referral pathways, and diagnostic delays. Oral involvement was present in all patients, and nine (39.1%) had high-risk disease. IgA deposition on direct immunofluorescence was detected in eight patients (34.8%) and was associated with high-risk disease (75.0% vs. 20.0%; p = 0.023) and differed across severity categories (p = 0.034). Oral symptoms were the initial presentation in 17 patients (73.9%), and dentistry was the most common first specialty consulted (56.5%). Gingivitis, periodontitis, or stomatitis was recorded at the first medical institution in 12 patients (52.2%), whereas autoimmune blistering disease was suspected in only three (13.0%). Median delays from symptom onset to the first medical consultation (patient delay), from the first consultation to definitive diagnosis (professional delay), and from symptom onset to definitive diagnosis (total diagnostic delay) were 1, 7, and 10 months, respectively. Professional delay was significantly longer than patient delay (p = 0.010) and exceeded it in 17 patients (73.9%). These findings from a regional tertiary dermatology center highlight professional delay as the predominant component of diagnostic delay and identify an exploratory association between IgA deposition on direct immunofluorescence and greater disease severity.

Background/Objectives: To compare the diagnostic performance of Claude Opus 4.7 and Gemini Pro 3 for the differential diagnosis of oral autoimmune blistering diseases (AIBDs) and evaluate their diagnostic reasoning, confidence, and calibration. Materials and Methods: This retrospective multicenter paired diagnostic accuracy study included 200 clinicopathologically confirmed AIBD cases (50 each of pemphigus vulgaris, mucous membrane pemphigoid, bullous pemphigoid, and linear IgA bullous dermatosis). Each case was independently assessed by both models using identical standardized clinical information and clinical photographic inputs. The task required forced-choice classification among the four predefined diseases. Histopathological and direct immunofluorescence findings were used exclusively to establish the clinicopathological reference diagnosis and were not provided to the AI models. The reference diagnosis was established by clinicopathological correlation. The primary outcome was diagnostic accuracy. Secondary outcomes included disease-specific diagnostic performance, Cohen's κ, ROC analysis, calibration, confidence, reasoning quality, management recommendations, and error patterns. Pre-consensus inter-rater reliability of the two human assessors was also evaluated using Cohen's κ for binary outcomes and weighted Cohen's κ for the ordinal reasoning-quality score. Results: Claude achieved significantly higher diagnostic accuracy than Gemini (92.0% vs. 86.0%, p = 0.012), stronger agreement with the reference standard (κ = 0.893 vs. 0.813), and superior discrimination (macro-AUC 0.998 vs. 0.965). Claude demonstrated higher key diagnostic-feature identification (92.0% vs. 86.0%; p = 0.012) and higher clinical-reasoning scores (61.0% vs. 40.0% of responses rated good; Wilcoxon p < 0.001; r = 0.47), whereas management recommendations did not differ significantly (100.0% vs. 98.0%; p = 0.125). Calibration results were metric-dependent: Claude had a lower one-vs-rest Brier score (0.0468 vs. 0.0558), whereas Gemini had a lower expected calibration error (0.083 vs. 0.251). For both models, the predominant error was misclassification of linear IgA bullous dermatosis as mucous membrane pemphigoid. Conclusions: Both multimodal LLMs showed high performance in this controlled four-class benchmark, with Claude Opus 4.7 outperforming Gemini Pro 3 in overall accuracy and reasoning quality. However, these findings do not establish autonomous diagnostic capability, clinical effectiveness, or safety. The LABD-MMP misclassification and metric-dependent calibration highlight important limitations. The models should therefore be regarded as investigational adjunctive decision-support tools requiring clinician oversight and diagnostic verification. Prospective external and human-in-the-loop validation is required before clinical implementation.

Desquamative gingivitis (DG) is a clinical sign characterized by gingival erythema, epithelial desquamation, and erosion rather than a discrete diagnosis. It most commonly reflects underlying oral lichen planus, mucous membrane pemphigoid, or pemphigus vulgaris. As affected patients typically present to general dental practitioners, timely recognition and structured triage are essential for effective management. However, diagnostic delays remain common and can extend the management period by several months. This narrative review synthesizes the current evidence on the clinical presentation, epidemiology, etiology, differential diagnosis, diagnostic workup, and management pathways relevant to general dentistry for this condition. Key findings indicate that a staged clinical history and examination can substantially narrow the differential diagnosis prior to biopsy, that histopathology combined with direct immunofluorescence offers superior diagnostic yield compared with histopathology alone, and that biopsy technique and site selection, favoring perilesional or uninvolved tissue and atraumatic sampling methods, meaningfully affect the diagnostic accuracy. Chronic ulcerative stomatitis and lichen planus pemphigoides are important but frequently overlooked mimics of more common causes. While disease-specific pharmacotherapy generally requires specialist oversight, professional oral hygiene reinforcement and gentle periodontal care delivered by general dental practitioners produce consistent, evidence-supported improvements in pain and lesion activity across all underlying diagnoses. A structured, practical approach to recognition, biopsy planning, and prompt referral can shorten the diagnostic pathway and improve long-term outcomes in patients with this challenging clinical condition.

BACKGROUND: Treatment with dipeptidyl peptidase-4 inhibitors (DPP-4i) is a strong risk factor for developing bullous pemphigoid, a dermatological disorder that is itself strongly associated with multiple sclerosis (MS). We therefore hypothesized that DPP-4i would also increase the risk of MS. OBJECTIVE: To investigate whether prior use of DPP-4i is associated with incident MS. METHODS: This nationwide register-based matched case-control study included individuals with incident MS identified by date of diagnosis (index date) in the Danish Multiple Sclerosis Registry between 2008 and 2023 matched 1:10 with population controls based on year of birth, gender, place of residence, and index date. Exposure was classified as a three-level mutually exclusive variable based on redeemed prescriptions at any time before the index date: any DPP-4i use, other type 2 diabetes medication use, or non-use. Conditional logistic regression was used to estimate odds ratios with 95% confidence intervals. RESULTS: A total of 9063 incident cases of MS and 90,630 controls were identified. The mean age at the index date was 41.36 years for patients with MS and 41.48 years for controls. Prior DPP-4i exposure was observed in 27 MS cases (0.30%) and 405 controls (0.45%), corresponding to an odds ratio of 0.67 (95% CI, 0.45-0.99) versus non-use. Other type 2 diabetes medication use was observed in 274 MS cases (3.02%) and 2474 controls (2.73%), corresponding to an odds ratio of 1.11 (95% CI, 0.98-1.26) versus non-use. CONCLUSION: DPP-4i use was not associated with an increased risk of MS and may be protective.