Allergies, Volume 6, Issue 2 (June 2026) – 8 articles

Background: Gestational diabetes mellitus (GDM) is an increasingly prevalent metabolic disorder of pregnancy. Beyond its well-established metabolic consequences, growing evidence suggests that exposure to maternal hyperglycemia during fetal life may influence immune system development and increase the risk of allergic diseases in offspring. Objective: This study aimed to systematically review the available evidence on the association between gestational diabetes mellitus and the development of allergic diseases in children, with particular emphasis on immunological mechanisms and the role of early-life gut microbiota. Methods: A systematic review was conducted using the PubMed and Scopus databases. Original human and animal studies, including cohort, case–control, cross-sectional, and clinical studies, were eligible for inclusion. Study selection followed PRISMA guidelines and was performed independently by three reviewers. Methodological quality was assessed using the Newcastle–Ottawa Scale (NOS) and Joanna Briggs Institute (JBI) Critical Appraisal Tools. Results: The included studies suggest that children born to mothers with GDM may have an increased risk of developing allergic diseases, particularly atopic dermatitis, food allergy, allergic rhinitis, and urticaria. Associations with childhood asthma were less consistent and appeared to depend on maternal body mass index, glycemic control, and duration of follow-up. Evidence suggests that maternal hyperglycemia may disrupt fetal immune programming through chronic low-grade inflammation, oxidative stress, altered cytokine profiles, and impaired regulatory T-cell development. Additionally, GDM has been associated with early alterations in neonatal gut microbiota composition and metabolic pathways, which may further contribute to immune dysregulation and increased susceptibility to allergic diseases. Importantly, effective metabolic control during pregnancy was associated with a lower risk of adverse allergic outcomes in offspring. Conclusions: GDM may represent an important prenatal exposure associated with altered immune maturation and a higher risk of allergic diseases in offspring. Early metabolic disturbances, immune dysregulation, and alterations in gut microbiota appear to be key mechanisms underlying this association. Optimizing glycemic control during pregnancy and implementing early-life preventive strategies may reduce the long-term burden of allergic diseases. Further well-designed longitudinal and mechanistic studies are required to clarify causal pathways and identify effective preventive interventions. Full article

Bacterial and fungal airway communities play a critical role in allergic respiratory diseases, yet they are often studied independently despite evidence of cross-kingdom ecological interactions. We investigated bacterial–fungal interactions across allergic rhinitis (AR), asthma (AS), allergic rhinitis with asthma comorbidity (ARAS), and healthy controls (HC) in a cohort of 286 participants (531 samples) using network analysis. Buccal and nasal samples were sequenced for 16S rRNA and ITS amplicons and networks constructed using sparse inverse covariance estimation for ecological association and statistical inference. Inferred bacterial–fungal connections comprised approximately one-third of the network edges. Taxonomic analyses of cross-kingdom-associated ASVs from the bacterial genera Dolosigranulum, Gamella, Haemophilus, Lawsonella, and Moraxella and the fungal genus Cladosporium revealed significant (p < 0.05) differences in mean relative abundance between the disease groups and healthy controls. Network topology analysis further identified distinct high-weight and high-degree microbial hubs, predominantly comprising fungal ASVs (Aleurina, Cladosporium, Malassezia, and Vishniacozyma) acting as putative keystone taxa and with disease-specific patterns. Together, these findings demonstrate that allergic airway diseases in this cohort are characterized by altered cross-kingdom network structure and disease-specific reorganization of microbial interaction patterns; this highlights the importance of integrated bacteriome–mycobiome analyses in understanding airway dysbiosis. Full article

Atopic dermatitis (AD) is a chronic, relapsing inflammatory dermatosis characterized by pruritus, eczematous lesions, and a fluctuating course. It imposes substantial quality-of-life and economic burdens through sleep disturbance, pain, psychosocial distress, and frequent healthcare utilization. Recent global estimates suggest AD affects hundreds of millions worldwide, with meaningful prevalence in both children and adults. AD pathogenesis is multifactorial, reflecting the interaction of genetic predisposition, immune dysregulation dominated by type 2 inflammation, epidermal barrier impairment, neuroimmune itch pathways, and microbial dysbiosis. Clinical diagnosis remains primarily clinical, supported by classic criteria emphasizing pruritus, typical morphology, chronicity, and atopic history. Disease severity and treatment response are commonly quantified using validated measures such as EASI and SCORAD, enabling standardized monitoring and evidence-based escalation. Management has shifted from broad immunosuppression to a stepwise, endotype-aware approach integrating barrier repair, anti-inflammatory topical therapy, phototherapy, conventional systemic agents, and rapidly expanding targeted options. Recent guidelines and approvals highlight increasing roles for biologics and JAK pathway inhibition, alongside newer nonsteroidal topicals. This review summarizes current concepts and practical treatment integration, with emphasis on safety, monitoring, and future research directions. Full article

Background: Cow’s milk protein allergy (CMPA) is a common cause of gastrointestinal and dermatologic symptoms in infancy. In clinical practice, infants with atopic dermatitis (AD) and suspected non-IgE-mediated CMPA are frequently managed with formula modification, although real-world comparative data across different formula strategies remain limited. Aim: To evaluate gastrointestinal symptom resolution, improvement in AD, and growth outcomes following formula modification in infants with AD and suspected non-IgE-mediated CMPA. Methods: This retrospective comparative cohort study included 107 infants aged ≤12 months with documented AD and suspected non-IgE-mediated CMPA evaluated at a tertiary academic center between January 2024 and December 2025. Infants were categorized according to initial management strategy: switch to extensively hydrolyzed formula (eHF; n = 63), switch to amino acid formula (AAF; n = 29), or continued standard cow’s milk-based formula (n = 15). The primary outcome was resolution of gastrointestinal symptoms within 2–4 weeks. Secondary outcomes included improvement in AD, weight gain, and need for further formula escalation. Multivariable logistic regression was performed to adjust for potential confounders. Results: Overall, gastrointestinal symptom resolution occurred in 74 of 107 infants (69.2%). Resolution rates were 71.4% in the eHF group, 79.3% in the AAF group, and 40% in the standard formula group (p = 0.01). In adjusted analysis, switching to eHF (aOR 2.8; 95% CI 1.1–7.3; p = 0.03) and AAF (aOR 4.1; 95% CI 1.3–12.5; p = 0.01) was independently associated with higher odds of symptom resolution compared with continued standard formula. Improvement in AD was observed in 57.9% of infants overall and differed significantly across groups (p = 0.04). Mean weight gain during follow-up did not differ significantly between groups (p = 0.63). Subsequent formula escalation was more frequent in the standard formula group (46.7%) compared with eHF (17.5%) and AAF (13.8%) groups (p = 0.004). Conclusions: In infants with AD and suspected non-IgE-mediated CMPA, substitution with extensively hydrolyzed or amino acid formula was independently associated with greater gastrointestinal symptom resolution and improvement in dermatitis compared with continued standard formula, without evidence of compromised growth. These findings provide supportive real-world evidence consistent with current international guidelines; however, given the observational design and potential for residual confounding, they should be interpreted as hypothesis-generating rather than confirmatory evidence of causal treatment effects. Full article

Chronic rhinosinusitis (CRS) is a heterogeneous inflammatory syndrome of the sinonasal mucosa that is imperfectly captured by phenotypes with or without nasal polyps. Since allergic rhinitis (AR) and atopy often occur alongside CRS, the term “allergic CRS” is commonly used. However, it is uncertain whether this term indicates a specific allergen-related, IgE-mediated endotype or merely represents a clinical overlap. We synthesize epidemiologic data, mucosal immunobiology, epithelial barrier dysfunction, and host–microbe interactions that can generate IgE-rich type 2 inflammation in CRS. We propose an operational entity test (objective CRS; clinically relevant allergy; evidence of IgE relevance in target tissue; exposure–response patterns; and differential response to allergy-directed interventions) to guide hypothesis testing rather than diagnosis. Using this framework, allergic fungal rhinosinusitis and central compartment atopic disease emerge as the clearest clinical prototypes where allergen contact patterns and IgE relevance plausibly contribute to disease expression. In contrast, microbial superantigens and other non-allergen stimuli can drive local IgE amplification, limiting the specificity of systemic sensitization as a causal marker. We discuss therapeutic implications, including biologics targeting type 2 pathways and epithelial alarmin blockade, and outline research priorities for endotype-resolved cohorts and mechanism-informed trials to test whether allergic CRS should evolve from a heuristic descriptor into a validated endotype. Full article

Background: High dietary salt intake has been implicated in immune-mediated inflammatory diseases; however, its impact on allergic contact dermatitis (ACD) remains unclear. This study examined whether dietary salt exposure during the sensitization phase influences the severity of DNFB-induced ACD in mice. Methods: Female C57BL/6N mice were fed a normal diet (ND) or an 8% high-salt diet (HSD). In a subset, salt intake was normalized prior to sensitization (HSD → ND). ACD was induced using a DNFB sensitization and challenge protocol. Ear swelling was quantified using incremental area under the curve (iAUC). Histological analyses and measurements of plasma and skin sodium were performed. Results: HSD-fed mice showed greater ear swelling and higher iAUC than ND controls, accompanied by enhanced inflammatory cell infiltration. Skin sodium concentration differed among groups, with a higher concentration in HSD-fed mice compared that in the HSD → ND group. Normalization of salt intake prior to sensitization attenuated disease severity. Spearman analyses indicated that total sodium intake and plasma potassium concentration were associated with inflammatory severity. Conclusions: Dietary salt exposure during immune sensitization exacerbated experimental ACD and was associated with systemic electrolyte alterations. These findings suggest that sodium exposure during immune activation may influence allergic skin inflammation. Full article

Chronic urticaria (CU) is a mast cell-driven inflammatory skin disorder characterized by recurrent wheals, angioedema, or both lasting more than six weeks, often resulting in significant impairment of quality of life. Although CU has traditionally been regarded as a predominantly histamine-mediated condition, evidence accumulated over the past decade has redefined chronic spontaneous urticaria (CSU) as a complex immune-mediated disease with marked biological heterogeneity. Distinct pathogenic mechanisms involving autoimmune pathways, dysregulated mast cell activation, and chronic inflammatory networks have been identified, providing a mechanistic basis for disease persistence, variable severity, and therapeutic refractoriness. This review synthesizes current concepts in CSU pathophysiology, with emphasis on mast cell biology, autoimmune endotypes, and inflammatory amplification mechanisms. We further discuss emerging biomarkers with potential relevance for disease stratification and treatment prediction, as well as established and novel therapeutic strategies targeting key pathogenic pathways. By integrating mechanistic insights with clinical implications, this review highlights the transition toward endotype-driven and biomarker-guided management of chronic urticaria. Full article