Dermatitis Herpetiformis in Celiac Disease: A Systematic Review and Meta-Analysis.

Dermatitis herpetiformis (DH) shares a pathophysiological basis with celiac disease (CD), but its epidemiology remains poorly defined. This systematic review and meta-analysis estimated the prevalence of DH among CD patients. Following the PRISMA 2020 guidelines, PubMed, Embase, Web of Science, and Scopus were searched. Observational studies with extractable DH data in CD patients were pooled using a random-effects model, with subgroup and meta-regression analyses. The risk of bias was assessed using the JBI Checklist. Of 7271 records, 24 studies published between 1996 and 2023, comprising 73,905 patients with celiac disease and 2203 DH cases (crude prevalence: 3.0%), met the inclusion criteria. Pooled DH prevalence in CD was 6.8% (95% CI: 5.0-9.3). When restricting the analysis to nonselected populations, the pooled prevalence was 6.7% (95% CI: 4.7-9.6). Prevalence was lower in pediatric CD (2.6%, 1.4-4.5) than in adults (8.6%, 5.8-12.6). Gender-specific prevalence, based on 5 of the 24 studies and not directly comparable with the overall estimate, was 12.9% (7.0-22.7) in males and 9.6% (3.7-22.9) in females. Sensitivity analyses yielded comparable estimates across all models (range: 6%-9%), indicating that the results were consistent across different methodological assumptions and not driven by specific study characteristics. Given the very high heterogeneity (I2 = 98.9%), the pooled estimate should be interpreted as an average across diverse settings rather than a single generalizable figure. These findings emphasize the need for standardized diagnostic approaches and more consistent reporting in clinical settings. TRIAL REGISTRATION: PROSPERO (CRD42023444060).