Presence of positive skin prick tests to inhalant allergens and markers of T2 inflammation in subjects with chronic spontaneous urticaria (CSU): a systematic literature review

[Recognition and management of relevant comorbidities in chronic spontaneous urticaria]

Various mechanisms contributing to the activity of chronic spontaneous urticaria (CU) have been postulated. Associated comorbidities are increasingly leading to the discovery of further signaling pathways which may support the activity of chronic urticaria or contribute to low-grade systemic inflammation. Moreover psychoimmunological factors may also be involved. The aim of this work is to improve the clinical care of patients with CU by increasing knowledge regarding optional influencing factors due to comorbidities and to possibly influence disease activity. Chronic urticaria due to autoimmune mechanisms may dispose to other autoimmune diseases, especially autoimmune thyroiditis, which can trigger chronic disease. Association of CU with metabolic syndrome has received little attention to date. Obesity may contribute to low-grade systemic inflammation by cytokine-secreting adipose tissue and hence to mediator-release of mast cells. Furthermore, neuroimmunological pathways, especially increased release of substance P, an activating ligand of Mas-related G protein-coupled receptor X2 (MRGPX2) on mast cells, should be addressed when optimizing therapy.

Atopy in chronic urticaria: an important yet overlooked issue

Chronic urticaria (CU) is one of the most common dermatological diseases and has a significant impact on the quality of life of patients. However, the pathogenesis of this disease remains unclear. Autoimmunity in chronic spontaneous urticaria (CSU) has received considerable attention and has been studied previously. Atopy is an important characteristic of CU; however, it has not been fully recognized. Atopy predisposes individuals to immune responses to allergens, leading to type 2 inflammation and immunoglobulin E (IgE) overproduction. Compared with healthy individuals, patients with CU have a higher proportion of atopy, and an atopic background is correlated with the clinical characteristics of CU. The total IgE levels in patients with CU is significantly higher than those in healthy individuals. Although its level is not higher than that in classic allergic diseases, it is closely related to CU. Exogenous allergens, auto-allergens, and specific IgEs, which are closely related to atopy, have been reported, and their roles in CU pathogenesis are also being studied. Local and systemic atopic inflammation is present in patients with CU. This review summarizes the current knowledge regarding atopy and CU, speculating that there are CU subtypes, such as atopic CSU or atopic chronic inducible urticaria (CIndU) and that atopy may be involved in the pathogenesis of CU. These findings provide a new perspective for a comprehensive understanding of the clinical features of CU and further research regarding its pathogenesis.

Atopy Does Not Influence the Clinical Outcome of Acute Urticaria: A Retrospective Study

BACKGROUND

Acute urticaria (AU) may be associated with atopy, but the relationship between atopic status and the clinical features of the disease has not been fully described.

OBJECTIVES

The aim of the study was to determine the proportion of atopy in AU patients and to see whether atopy is related to the clinical characteristics of AU and whether it has an impact on the outcome of the disease.

MATERIALS AND METHOD

A retrospective analysis of patients with AU was performed. Demographic data, clinical features, and laboratory results were compared and analyzed between the atopic and non-atopic AU (napAU).

RESULTS

In total, 139 participants were included. 54 (38.8%) patients were atopic AU (apAU) and 85 (61.2%) were napAU. Compared with napAU patients, apAU patients were more likely to have anaphylaxis, higher levels of C4, and lower levels of antistreptolysin. There were no significant differences between the two groups in terms of other clinical features, laboratory tests, the natural course of the disease, or disease outcomes.

CONCLUSION

Atopy does exist in some patients with AU, and AU patients with an atopic background are at higher risk for anaphylaxis. Atopy does not influence the clinical outcome of AU and is not correlated with other clinical features and laboratory results of AU.

Differences between adult and pediatric chronic spontaneous urticaria from a cohort of 751 patients: Clinical features, associated conditions and indicators of treatment response

BACKGROUND

Chronic spontaneous urticaria (CSU) is a common disease both in the pediatric and in the adult population. However, there are differences between the two patient populations with respect to etiological factors, comorbidities, and treatment responses. Our aim was to determine differences between pediatric and adult CSU in terms of clinical characteristics, laboratory parameters, comorbidities, response to treatment, and indicators of response.

METHODS

A retrospective analysis of CSU patients was performed. Data regarding differences between pediatric and adult CSU patients were analyzed. Indicators of treatment response were determined separately in both pediatric and adult patients.

RESULTS

Of 751 CSU patients (162 pediatrics and 589 adults), female dominancy (48.8% vs. 69.6%) and rate of angioedema (19.1% vs. 59.8%) were lower, and disease duration (5 months vs. 12 months) was shorter in pediatric patients. Anti-TPO positivity (24.7% vs. 9%), elevated CRP (46.5% vs. 11.1%), eosinopenia (38.5% vs. 18.1%), and skin prick test positivity (39.3% vs. 28.8%) were significantly more frequent in adult patients. Response to antihistamines was higher in the pediatric group, and only 7% used omalizumab versus 20.8% in the adults. The comparisons were also performed between <12-year and ≥12-year patients and yielded similar results.

CONCLUSION

Pediatric CSU shows distinct characteristics such as lower incidence of angioedema and antithyroid antibodies, and it responds better to antihistamines. These suggest that CSU becomes more severe and refractory in adolescents and adults. Adolescent CSU shows features similar to adult CSU rather than pediatric CSU.

DNA methylation regulatory patterns and underlying pathways behind the co-pathogenesis of allergic rhinitis and chronic spontaneous urticaria

Background

Allergic rhinitis (AR) and chronic spontaneous urticaria (CSU) are often concurrent in patients. Changes in DNA methylation affect T cell biological processes, which may explain the occurrence and progression of comorbidity. However, downstream regulatory pathways of DNA methylation in two diseases and the underlying mechanisms have not been fully elucidated.

Methods

The GSE50101, GSE72541, GSE50222 and OEP002482 were mined for the identification of differentially expressed genes (DEGs) or co-expressed genes and differentially methylated genes (DMGs) in AR and CSU patients. We applied GO analysis and consensus clustering to study the potential functions and signal pathways of selected genes in two diseases. GSVA and logistic regression analysis were used to find the regulatory pathway between DNA methylation and activation patterns of CD4+ T cells. Besides, we used the Illumina 850k chip to detect DNA methylation expression profiles and recognize the differentially methylated CpG positions (DMPs) on corresponding genes. Finally, we annotated the biological process of these genes using GO and KEGG pathway analysis.

Result

The AR-related DEGs were found closely related to the differentiation and activation of CD4+ T cells. The DEGs or co-expressed genes of CD4+ T cells in AR and CSU patients were also clustered using GO and KEGG analysis and we got 57 co-regulatory pathways. Furthermore, logistic regression analysis showed that the regulation of cellular component size was closely related to the activation of CD4+ T cells regulated by DNA methylation. We got self-tested data using the Illumina 850k chip and identified 98 CpGs that were differentially methylated in patients. Finally, we mapped the DMPs to 15 genes and found that they were mainly enriched in the same CD4+T cell regulating pathway.

Conclusion

Our study indicated that DNA methylation affected by pollen participated in the activation patterns of CD4 + T cells, providing a novel direction for the symptomatic treatment of the co-occurrence of AR and CSU.

Patients with allergic asthma have lower risk of severe COVID-19 outcomes than patients with nonallergic asthma

Background

Although asthma does not appear to be a risk factor for severe coronavirus disease 2019 (COVID-19), outcomes could vary for patients with different asthma subtypes. The objective of this analysis was to compare COVID-19 outcomes in real-world cohorts in the United States among patients with asthma, with or without evidence of allergy.

Methods

In a retrospective analysis of the COVID-19 Optum electronic health record dataset (February 20, 2020–January 28, 2021), patients diagnosed with COVID-19 with a history of moderate-to-severe asthma were divided into 2 cohorts: those with evidence of allergic asthma and those without (nonallergic asthma). After 1:1 propensity score matching, in which covariates were balanced and potential bias was removed, COVID-19 outcomes were compared between cohorts.

Results

From a COVID-19 population of 591,198 patients, 1595 patients with allergic asthma and 8204 patients with nonallergic asthma were identified. After propensity score matching (n = 1578 per cohort), risk of death from any cause after COVID-19 diagnosis was significantly lower for patients with allergic vs nonallergic asthma (hazard ratio, 0.48; 95% CI 0.28–0.83; P = 0.0087), and a smaller proportion of patients with allergic vs nonallergic asthma was hospitalized within − 7 to + 30 days of COVID-19 diagnosis (13.8% [n = 217] vs 18.3% [n = 289]; P = 0.0005). Among hospitalized patients, there were no significant differences between patients with allergic or nonallergic asthma in need for intensive care unit admission, respiratory support, or COVID-19 treatment.

Conclusions

Asthma subtype may influence outcomes after COVID-19; patients with allergic asthma are at lower risk for hospitalization/death than those with nonallergic asthma.

Prevalence, predictors, and clinical relevance of α-gal sensitization in patients with chronic urticaria

Background

Little is known about α‐gal (galactose‐α‐1,3‐galactose) sensitization in patients with chronic urticaria (CU). The aim of this study was to examine the prevalence, predictors and clinical relevance of α‐gal sensitization in patients with CU.

Methods

Two consecutive cohorts of newly referred patients with CU from a primary care allergology practice and a tertiary hospital dermatology department, plus a control group with allergic disease, but not CU, from the allergology practice, were interviewed and screened for α‐gal sensitization (serum specific‐IgE ≥0.35 KU/L).

Results

Of 733 patients included, 21 (5.6%) and 11 (3.9%) of CU patients from private practice and hospital, respectively, were α‐gal sensitized. In total, 8 patients (38.1% of sensitized patients, and 2.1% of all CU patients) from private practice, and 2 patients (18.2% of sensitized patients, and 0.7% of all CU patients) from hospital, had clinically relevant α‐gal allergy. In private practice, male sex (47.6 vs. 24.7%), p = 0.020, obesity (33.3 vs. 23.6%), p = 0.302, and frequency of angioedema (61.9 vs. 51.4%), p = 0.350; and in hospital, male sex (72.7 vs. 27.9%), p = 0.003, and high total immunoglobulin E (median 168 vs. 70.5 KU/L), p = 0.022 were associated with α‐gal sensitization.

Conclusion

α‐gal sensitization is observed in a small fraction of CU patients with only few patients experiencing clinically relevant sensitization. Certain patients, particularly from primary care, may constitute a relevant population for aimed testing.

Aeroallergens in Atopic Dermatitis and Chronic Urticaria

PURPOSE OF REVIEW

While aeroallergens are a well-established trigger of asthma and allergic rhinitis, their role in allergic skin diseases such as atopic dermatitis and chronic urticaria remains controversial. This paper reviews the pathophysiology and clinical evidence for aeroallergens in these allergic skin diseases and summarizes current strategies for evaluation and management.

RECENT FINDINGS

Current evidence implicates aeroallergens as triggers of cutaneous reactions in atopic dermatitis. Direct skin contact is the likely route of trigger. Aeroallergens may also trigger chronic urticaria, though mechanistic studies are limited. These allergens may cross the skin barrier and directly trigger neurons to release substance P, resulting in mast cell degranulation and dumping of histamine and prostaglandin D2. Many studies link aeroallergen sensitization to chronic urticaria, and case reports suggest the utility of avoidance strategies. The role of aeroallergens as a trigger is clear in atopic dermatitis and becoming emergent in chronic urticaria. Skin prick testing or serum-specific immunoglobulin E testing may be used to determine sensitivities. Management at this time centers on avoidance, and further studies are necessary to evaluate the efficacy of aeroallergen immunotherapy for both conditions.

Association Between a Type 2 Inflammatory Disease Burden Score and Outcomes Among Patients with Asthma

Background

Although prevalence of co-existing type 2 inflammatory diseases (cT2) in asthma patients has been reported, limited data exist regarding their impact on asthma outcomes.

Objective

To assess the impact of cT2 burden on asthma outcomes and to evaluate patterns of clustering of cT2 in a real-world setting.

Methods

From medical records of 4.5 million enrollees in 650 primary care practices in the UK (January 2010–December 2017), patients with ≥1 diagnosis code for asthma at any time pre-index date (date of most recent asthma-related medical encounter) and ≥2 asthma-related prescriptions during the year before index date were categorized into the Global Initiative of Asthma (GINA) guideline severity steps. A cT2 burden score (range 0–9) was assigned based on the total number of co-existing conditions (allergic conjunctivitis, allergic rhinitis, anaphylaxis, eczema/atopic dermatitis, chronic rhinosinusitis, eosinophilic esophagitis, food allergy, nasal polyps, or urticaria) for which patients received a medical diagnosis. Multivariate regression models evaluated associations between cT2 burden score and asthma exacerbations and asthma control. Factor analysis was performed to assess which cT2 comorbidities were correlated and exhibited patterns of clustering.

Results

Overall, 245,893 patients with asthma were included (mean [SD] age 44.8 [22.1] years; 43.8% male). Between 55% (GINA step 1) and 60% (GINA step 5) of asthma patients had a medical diagnosis for ≥1 other type2dx. Patients with increased cT2 burden were significantly more likely to experience asthma exacerbations and less likely to achieve asthma control.

Conclusion

Asthma patients with a higher cumulative cT2 burden score were more likely to experience worse asthma outcomes than those without any cT2 (burden score of 0).