Pollen–food allergy syndrome (PFAS), also known as oral allergy syndrome, is a common condition affecting individuals sensitized to pollens such as birch, ragweed, and grass. This syndrome arises from immunological cross-reactivity between pollen allergens and structurally similar proteins found in various fruits, vegetables, and nuts. Although typically presenting with mild oral and pharyngeal symptoms, PFAS can occasionally result in severe allergic reactions, underscoring its clinical significance. This review explores the pathophysiology of PFAS, highlighting the molecular mechanisms underlying cross-reactivity and examining the main protein families involved, including those contributing to variations in symptom severity. Current diagnostic approaches, including skin prick testing, specific immunoglobulin E measurements, and component-resolved diagnostics, are discussed. Emerging diagnostic tools and biomarkers with potential to enhance accuracy are also examined. Therapeutic strategies for PFAS primarily focus on symptom management and avoidance of trigger foods. However, novel approaches such as allergen immunotherapy and biologics targeting key immune pathways are gaining traction as potential interventions for more severe or refractory cases. By addressing the diagnostic and therapeutic challenges of PFAS, this paper aims to provide clinicians and researchers with a comprehensive understanding of this condition, fostering improved patient care and the development of innovative treatment strategies.

Emerging evidence suggests a critical role of the gut microbiome in modulating systemic immune responses, with increasing relevance in dermatological diseases. Chronic spontaneous urticaria (CSU), traditionally viewed as an isolated cutaneous disorder, is now recognized as a systemic immune condition involving complex interactions between innate and adaptive immunity, mast cell dysregulation, and non-IgE-mediated pathways. This review explores the gut–skin axis as a unifying concept linking intestinal dysbiosis to inflammatory skin diseases, including atopic dermatitis, psoriasis, rosacea, and acne. Special emphasis is placed on CSU, where altered gut microbial composition, characterized by reduced diversity, depletion of short-chain fatty acid-producing bacteria, and expansion of Proteobacteria, may contribute to increased intestinal permeability, systemic immune activation via toll-like receptors, and heightened mast cell sensitivity. We discuss findings from animal models demonstrating that gut microbiota modulation can attenuate mast cell hyperreactivity and reduce urticarial symptoms. In parallel, we examine clinical evidence supporting the potential role of probiotics, prebiotics, dietary interventions, and fecal microbiota transplantation as adjunctive strategies in CSU management. Despite promising findings, challenges remain in translating microbiome research into effective therapies due to interindividual variability, the complexity of host–microbiome interactions, and a lack of standardized protocols. Future research should focus on identifying predictive microbial patterns and developing personalized microbiome-targeted interventions. Understanding the bidirectional gut–skin relationship may open new therapeutic avenues beyond symptomatic treatment, positioning the microbiome as a novel target in CSU and related inflammatory dermatoses.

Asthma and atherosclerosis are chronic conditions with distinct pathophysiologies, but overlapping inflammatory mechanisms that suggest a potential common regulatory framework. MicroRNAs (miRNAs), small non-coding RNA molecules that modulate gene expression post-transcriptionally, could be key players in linking these disorders. This review outlines how miRNAs contribute to the complex interplay between asthma and atherosclerosis, focusing on key miRNAs involved in inflammatory pathways, immune cell regulation and vascular remodeling. We discuss specific miRNAs, such as miR-155, miR-21 and miR-146a, which have been shown to modulate inflammatory cytokine production and T cell differentiation, impacting respiratory and cardiovascular health. The common miRNAs found in both asthma and atherosclerosis emphasize their role as potential biomarkers, but also as therapeutic targets. Understanding these molecular connections may unlock novel approaches for innovative, integrated treatment strategies that address both conditions and may significantly improve patient outcomes. Further research is needed to explore mechanistic pathways and validate the translational potential of miRNA-based interventions in preclinical and clinical settings.

Background: Asthma and atherosclerosis frequently coexist in clinical populations and share convergent immunometabolic pathways amplified by gut microbial dysbiosis. We propose the gut–lung–vascular axis as a unifying mechanistic framework connecting epithelial and endothelial inflammation providing a foundation for understanding shared inflammatory mechanisms beyond tissue-specific disease boundaries. Methods: A targeted narrative review systematically appraised clinical, experimental and multi-omics studies published over the last five years to delineate microbiota-driven pathways relevant to asthma and atherosclerosis. Particular emphasis was placed on specific microbial taxa, metabolite profiles and immunometabolic networks that connect gut dysbiosis with respiratory and cardiovascular dysfunction. Results: Across human and experimental cohorts, dysbiosis marked by depletion of short-chain fatty acids (SCFAs) producing taxa (Faecalibacterium, Roseburia, Bacteroides) and enrichment of pathobionts (Proteobacteria, Haemophilus, Moraxella, Streptococcus) promotes epithelial and endothelial barrier dysfunction, amplifying Th2/Th17-skewed inflammation and endothelial injury. Key metabolites, including SCFAs, trimethylamine N-oxide (TMAO), secondary bile acids (BA), indole/tryptophan derivatives and lipopolysaccharides (LPS), serve as molecular connectors linking gut, airway and vascular inflammation. Microbial signatures and metabolomic patterns hold emerging diagnostic and therapeutic potential, and several drug classes (e.g., statins, corticosteroids, proton-pump inhibitors (PPIs)) further modulate host–microbiota interactions. Conclusions: Shared microbial taxa and metabolite signatures in asthma and atherosclerosis support microbiota-mediated immune dysregulation along the gut–lung–vascular axis as a common pathogenic framework. Microbial and metabolite profiling may enable improved risk stratification and precise, microbiota-targeted therapies. Integrating microbiome-informed diagnostics and personalized interventions could help reduce systemic inflammation and the burden of these overlapping inflammatory diseases.

Background/Objectives: Amb a 1 is the major allergenic component of Ambrosia artemisiifolia pollen and a clinically relevant marker of genuine ragweed sensitization. Heart failure is increasingly recognized as a systemic syndrome shaped by immune activation, endothelial dysfunction, fibrosis, neurohormonal imbalance, pulmonary comorbidity, and environmental exposures. This narrative review aims to synthesize the translational evidence linking Amb a 1-specific IgE, IgE-mediated inflammation, allergic airway disease, and cardiovascular remodeling in heart failure. Methods: A targeted narrative review was performed, integrating evidence on component-resolved ragweed diagnosis, IgE-FcεRI signaling, mast cell and eosinophil biology, pollen exposure, cardiovascular inflammation, and heart failure pathophysiology. Results: No dedicated clinical studies have validated Amb a 1-specific IgE as a diagnostic, prognostic, or therapeutic biomarker in heart failure. However, adjacent evidence supports biologically plausible links between allergen-specific IgE responses and cardiovascular dysfunction, including mast cell activation, cytokine release, endothelial perturbation, oxidative stress, microvascular dysfunction, pulmonary-cardiac interaction, and myocardial fibrosis. Amb a 1-specific IgE may therefore identify a seasonally vulnerable heart failure phenotype, particularly in patients with allergic rhinitis, asthma, eosinophilic inflammation, or recurrent symptom worsening during ragweed season. A systemic/indirect pathway operating through allergic airway disease is distinguished from a postulated direct cardiac pathway; the latter remains strictly speculative, as no direct evidence demonstrates that inhaled Amb a 1 reaches or activates cardiac mast cells in vivo. Conclusions: Amb a 1-specific IgE should not currently be used to infer cardiac causality or modify heart failure therapy. Prospective, phenotype-rich, exposure-informed studies are needed to determine whether ragweed sensitization has clinically meaningful implications for heart failure endotyping, seasonal risk assessment, and cardio-allergology care. These findings may inform patient-centered heart failure management by improving the interpretation of seasonal dyspnea, allergic comorbidity, and symptom fluctuations in ragweed-endemic regions.