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Environmental Research Feb 2020Thunderstorm asthma is defined as epidemics of asthma occurring shortly after a thunderstorm. While grass pollen has been implicated in thunderstorm asthma events,...
BACKGROUND
Thunderstorm asthma is defined as epidemics of asthma occurring shortly after a thunderstorm. While grass pollen has been implicated in thunderstorm asthma events, little is known about the role of fungi and studies have not been synthesised.
OBJECTIVE
This systematic review aims to evaluate whether grass pollen is necessary in thunderstorm asthma events and whether fungi also play a part in these associations.
METHODS
We conducted a systematic search using six electronic databases (i.e. CINAHL, Medline (Ovid), Web of Science, ProQuest Central, EMBASE and Google Scholar) and checked reference lists. The search terms used were pollen AND thunderstorm* AND asthma. The inclusion criteria were studies published in English with original human data relating to outdoor pollen and thunderstorm asthma.
RESULTS
Twenty of 2198 studies were eligible. Reported findings differed due to variation in methodological approaches and a meta-analysis was not possible. Nonetheless, of the 20 studies included, 15 demonstrated some relationship with nine demonstrating lagged effects up to four days for increasing grass pollen counts associated with increased risk of thunderstorm asthma. Of the 10 studies that examined fungi, nine demonstrated a positive relationship with thunderstorm asthma. The fungal taxa involved varied, depending on whether measurements were recorded before, during or after the thunderstorm. Nevertheless, none of the studies considered fungi as a potential effect modifier for the pollen-thunderstorm asthma association.
CONCLUSION
We found evidence to suggest that grass pollen was a necessary factor for thunderstorm asthma but there are other as yet unrecognised environmental factors that may also be important. Further research is required to examine the role of fungi and other environmental factors such as air quality as potential effect modifiers of the association.
Topics: Allergens; Asthma; Fungi; Humans; Poaceae; Pollen
PubMed: 31759647
DOI: 10.1016/j.envres.2019.108911 -
Cureus Jul 2022The treatment of allergic rhinitis is important due to the burden that the disease causes globally. The objective of this review is to explore the efficiency of house... (Review)
Review
BACKGROUND
The treatment of allergic rhinitis is important due to the burden that the disease causes globally. The objective of this review is to explore the efficiency of house dust mite and grass pollen extracts in allergic rhinitis treatment.
METHODS
We performed research in electronic databases and searched relevant articles on PubMed, CINAHL, OVID, ScienceDirect, Cochrane CENTRAL, and MEDLINE. We used keywords such as 'allergic rhinitis', 'sublingual immunotherapy', 'randomized controlled trials', 'grass pollen', 'allergen immunotherapy', and 'house dust mite'. We included nine randomized controlled trials (RCTs). Quality assessment of included studies was performed independently by two authors.
RESULTS
We included nine eligible RCTs in this review. Five RCTs were about grass pollen extracts and four RCTs were about house dust mite extracts. Most of the studies reported positive results and suggested further evaluation of sublingual immunotherapy (SLIT) treatment. Grass pollen extracts mostly used were Dactylis glomerata, Poa pratensis, Lolium perenne, Anthoxanthum odoratum, Phleum pratense, and Parietaria. House dust mite extracts used were from Dermatophagoides pteronyssinus and Dermatophagoides farina. According to the quality assessment, no bias was observed in the included studies.
CONCLUSIONS
Although sublingual allergen immunotherapy shows a benefit compared to placebo in the treatment of allergic rhinitis and rhino-conjunctivitis in adults, the results are interpreted with caution due to the high heterogenicity among studies in treatment protocols and dosing. More standardization among studies is needed.
PubMed: 36039254
DOI: 10.7759/cureus.27289 -
The Journal of Asthma : Official... Sep 2021We aimed to conduct a systematic review examining the association between outdoor pollen and childhood asthma hospitalizations.A systematic search of articles in... (Meta-Analysis)
Meta-Analysis
We aimed to conduct a systematic review examining the association between outdoor pollen and childhood asthma hospitalizations.A systematic search of articles in MEDLINE, EMBASE, CINAHL, ProQuest Central, Web of Science and Google Scholar published to 18 July 2019. Studies that presented data on pollen exposure and childhood asthma hospitalization were included and evaluated for potential risk of bias by two independent authors. Random effects meta-analysis was performed where possible.A total of 1048 records were identified, and twelve studies included in the review. The synthesis suggested possible associations between outdoor pollen, especially for grass and birch and childhood asthma hospitalization. However, the results varied widely across geographical areas and settings for other pollen taxa. The meta-analysis of the case-crossover studies showed a positive association between grass and childhood asthma hospitalization, an increase in 10 grass pollen grains/m was associated with a 3% increase in childhood asthma admission (OR = 1.03; 95%CI:1.01, 1.04), but the pooled estimate was not significant for timeseries studies. The meta-analysis of the timeseries studies for birch pollen showed an increase in 10 pollen grains/m being significantly associated with a Mean Percentage Change (MPC) in childhood asthma admissions (MPC= 0.85; 95%CI:0.40, 1.30). Globally, grass and birch pollen are important triggers of childhood asthma hospitalization, but the association could not be ascertained for other pollen taxa. Pollen is a major environmental trigger of asthma exacerbations and more focus on early interventions to reduce this burden needs to be considered.
Topics: Adolescent; Allergens; Asthma; Betula; Child; Child, Preschool; Hospitalization; Humans; Infant; Infant, Newborn; Poaceae; Pollen
PubMed: 32419541
DOI: 10.1080/02770903.2020.1771726 -
Frontiers in Immunology 2023To systematically compare the efficacy and safety of subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) in children with allergic rhinitis (AR). (Meta-Analysis)
Meta-Analysis
AIM
To systematically compare the efficacy and safety of subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) in children with allergic rhinitis (AR).
METHODS
PubMed, Embase, Cochrane Library, and Web of Science were searched from inception to March 2, 2023. Outcomes included symptom scores (SSs), medication scores (MSs), symptom and medication scores (SMSs), new sensitizations, development of asthma, improvement, and treatment-related adverse events (TRAEs). The quality of the included studies was assessed by the modified Jadad scale and Newcastle-Ottawa scale (NOS). Meta-regression was carried out to explore the source of heterogeneity. Subgroup analysis was further conducted in terms of study design [randomized controlled trials (RCTs), cohort studies], allergen [house dust mites (HDMs), grass pollen], treatment duration (≥ 24, 12-23 or < 12 months), allergen immunotherapy (AIT) modality (drops or tablets), and AIT protocol [continuous, pre-seasonal, co-seasonal, or after the grass pollen season (GPS)]. Sensitivity analysis was conducted for all outcomes. A Bayesian framework and a Monte Carlo Markov Chain (MCMC) model were developed for indirect comparison.
RESULTS
Totally 50 studies with 10813 AR children were included, with 4122 treated with SLIT, 1852 treated with SCIT, and 4839 treated with non-SLIT or non-SCIT therapy. For direct comparison, the SLIT group had a similar SS to the SCIT group [pooled standardized mean difference (SMD): 0.41, 95% confidence interval (CI): -0.46, 1.28, = 0.353]. Comparable MSs were observed in the SLIT and SCIT groups (pooled SMD: 0.82, 95%CI: -0.88, 2.53, = 0.344). For indirect comparison, no significant differences were found in SSs (pooled SMD: 1.20, 95% credibility interval (CrI): -1.70, 4.10), MSs (pooled SMD: 0.57, 95%CrI: -1.20, 2.30), SMSs (pooled SMD: 1.80, 95%CrI: -0.005, 3.60), new sensitizations [pooled relative risk (RR): 0.34, 95%CrI: 0.03, 3.58], and development of asthma (pooled RR: 0.68, 95%CrI: 0.01, 26.33) between the SLIT and SCIT groups; the SLIT group illustrated a significantly lower incidence of TRAEs than the SCIT group (pooled RR: 0.17, 95%CrI: 0.11, 0.26).
CONCLUSION
Considering both efficacy and safety, SLIT might be a more favorable AIT than SCIT in the treatment of pediatric AR, which may serve as a decision-making reference for clinicians.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO (CRD42023460693).
Topics: Child; Humans; Allergens; Asthma; Desensitization, Immunologic; Pollen; Rhinitis, Allergic; Immunotherapy; Sublingual Immunotherapy
PubMed: 38162647
DOI: 10.3389/fimmu.2023.1274241 -
International Journal of Biometeorology Oct 2021Climate and weather directly impact plant phenology, affecting airborne pollen. The objective of this systematic review is to examine the impacts of meteorological... (Review)
Review
Climate and weather directly impact plant phenology, affecting airborne pollen. The objective of this systematic review is to examine the impacts of meteorological variables on airborne pollen concentrations and pollen season timing. Using PRISMA methodology, we reviewed literature that assessed whether there was a relationship between local temperature and precipitation and measured airborne pollen. The search strategy included terms related to pollen, trends or measurements, and season timing. For inclusion, studies must have conducted a correlation analysis of at least 5 years of airborne pollen data to local meteorological data and report quantitative results. Data from peer-reviewed articles were extracted on the correlations between seven pollen indicators (main pollen season start date, end date, peak date, and length, annual pollen integral, average daily pollen concentration, and peak pollen concentration), and two meteorological variables (temperature and precipitation). Ninety-three articles were included in the analysis out of 9,679 articles screened. Overall, warmer temperatures correlated with earlier and longer pollen seasons and higher pollen concentrations. Precipitation had varying effects on pollen concentration and pollen season timing indicators. Increased precipitation may have a short-term effect causing low pollen concentrations potentially due to "wash out" effect. Long-term effects of precipitation varied for trees and weeds and had a positive correlation with grass pollen levels. With increases in temperature due to climate change, pollen seasons for some taxa in some regions may start earlier, last longer, and be more intense, which may be associated with adverse health impacts, as pollen exposure has well-known health effects in sensitized individuals.
Topics: Allergens; Climate Change; Humans; Pollen; Seasons; Temperature; Weather
PubMed: 33877430
DOI: 10.1007/s00484-021-02128-7 -
Clinical and Experimental Allergy :... May 2021Experimental challenge studies have shown that pollen can have early and delayed effects on the lungs and airways. Here, we qualitatively and quantitatively synthesize... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Experimental challenge studies have shown that pollen can have early and delayed effects on the lungs and airways. Here, we qualitatively and quantitatively synthesize the evidence of outdoor pollen exposure on various lung function and airway inflammation markers in community-based studies.
METHODS
Four online databases were searched: Medline, Web of Science, CINAHL and Google Scholar. The search strategy included terms relating to both exposure and outcomes. Inclusion criteria were human-based studies published in English that were representative of the community. Additionally, we only considered cross-sectional or short-term longitudinal studies which investigated pollen exposure by levels or season. Study quality assessment was performed using the Newcastle-Ottawa scale. Meta-analysis was conducted using random-effects models.
RESULTS
We included 27 of 6551 studies identified from the search. Qualitative synthesis indicated associations between pollen exposure and predominantly type-2 inflammation in both the upper and lower airways, but little evidence for lung function changes. People with ever asthma and/or seasonal allergic rhinitis (SAR) were at higher risk of such airway inflammation. Meta-analysis confirmed a positive relationship between pollen season, eosinophilia and eosinophil cationic protein (ECP) in people with ever SAR but the results between studies were highly variable. Heterogeneity was reduced after further subgrouping by age, and the forest plots indicated that eosinophilic airway inflammation to outdoor pollen exposure increased with age.
CONCLUSION
Among people with ever asthma and ever SAR, exposure to increased ambient pollen triggers type-2 upper and lower airway inflammation rather than a non-specific or innate inflammation. These findings can lead to the formulation of specific pollen immunotherapy for susceptible individuals. Future research should be directed towards investigating lagged associations and effect modifications using larger and more generalized populations.
SYSTEMATIC REVIEW REGISTRATION
CRD42020146981 (PROSPERO).
Topics: Asthma; Desensitization, Immunologic; Eosinophil Cationic Protein; Eosinophilia; Humans; Inflammation; Lung; Rhinitis, Allergic, Seasonal
PubMed: 33539034
DOI: 10.1111/cea.13842 -
Frontiers in Allergy 2024Birch pollen-related food allergy (BPFA) is the most common type of food allergy in birch-endemic areas such as Western and Central Europe. Currently, there is no... (Review)
Review
BACKGROUND
Birch pollen-related food allergy (BPFA) is the most common type of food allergy in birch-endemic areas such as Western and Central Europe. Currently, there is no treatment available for BPFA. Due to the cross-reactivity between birch pollen and a range of implicated plant foods, birch pollen allergen immunotherapy (AIT) may be effective in the treatment of BPFA. In this study, we systematically evaluate the effectiveness of birch pollen-specific subcutaneous or sublingual immunotherapy in treating BPFA.
METHODS
A search was performed in the PubMed, Embase, and Cochrane libraries. Studies were independently screened by two reviewers against predefined eligibility criteria. The outcomes of interest were changes in (1) severity of symptoms during food challenge, (2) eliciting dose (ED), and (3) food allergy quality of life (FA-QoL). The validity of the selected articles was assessed using the revised Cochrane risk of bias tool. We focused on studies with the lowest risk of bias and considered studies with a high risk of bias as supportive. Data were descriptively summarized.
RESULTS
Ten studies were selected that included 475 patients in total. Seven studies were categorized into "high risk of bias" and three into "moderate risk of bias." The three moderate risk of bias studies, with a total of 98 patients, reported on severity of symptoms during challenge and on the ED. All three studies had a control group. Compared to the control group, improvement in severity of symptoms was observed during challenge in two out of the three studies and on the eliciting dose in one out of three. Only one study investigated the effect of birch pollen AIT on FA-QoL, showing that there was no significant difference between patients receiving subcutaneous immunotherapy or a placebo. Of the seven supportive studies, four had a control group and of those, three showed improvement on both severity of symptoms and ED. None of the supportive studies investigated the effect of the therapy on FA-QoL.
CONCLUSION
This systematic review shows that there is not enough evidence to draw firm conclusions about the effect of AIT on BPFA. Future research is warranted that uses robust clinical studies that include long-term effects, QoL, and multiple BPFA-related foods.
PubMed: 38903704
DOI: 10.3389/falgy.2024.1360073 -
BMJ Open Jan 2020Several studies have assessed effects of short-term exposure to pollen on allergic and asthmatic manifestations. The evidence is inconclusive, and no meta-analysis has... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Several studies have assessed effects of short-term exposure to pollen on allergic and asthmatic manifestations. The evidence is inconclusive, and no meta-analysis has been published.
OBJECTIVE
To synthesise the evidence on the relations between short-term pollen exposure and the risk of allergic and asthmatic manifestations.
METHODS
We performed a systematic literature search of PubMed and Scopus databases up to the end of August 2018. In addition, we reviewed the reference lists of relevant articles. Two authors independently evaluated the eligible articles and extracted relevant information in a structured form. We calculated summary effect estimates (EE) based on the study-specific ORs and regression coefficients (β) by applying both fixed-effects and random-effects models.
RESULTS
26 studies met the a priori eligibility criteria, and 12 of them provided sufficient information for the meta-analysis. The summary EE related to 10 grains per m³ increase in pollen exposure showed an 1% increase (EE 1.01, 95% CI 1.00 to 1.02) in the risk of lower respiratory symptoms and a 2% increase (EE 1.02, 95% CI 1.01 to 1.03) in the risk of any allergic or asthmatic symptom. Correspondingly, the risk of upper respiratory symptoms and ocular symptoms increased 7% (EE 1.07, 95% CI 1.04 to 1.09) and 11% (EE 1.11, 95% CI 1.05 to 1.17), respectively, in relation to such pollen exposure. Short-term exposure to pollen did not show any significant effect on daily lung function levels.
CONCLUSION
Our results provide new evidence that short-term pollen exposure significantly increases the risks of allergic and asthmatic symptoms.
Topics: Allergens; Asthma; Environmental Exposure; Humans; Hypersensitivity; Pollen; Prevalence; Respiratory Function Tests; Risk Factors; Seasons; Severity of Illness Index
PubMed: 31924628
DOI: 10.1136/bmjopen-2019-029069 -
Journal of Investigational Allergology... Dec 2022Eosinophilic esophagitis is a chronic antigen-mediated esophageal disease characterized clinically by symptoms related to esophageal dysfunction and histologically by... (Review)
Review
Eosinophilic esophagitis is a chronic antigen-mediated esophageal disease characterized clinically by symptoms related to esophageal dysfunction and histologically by TH2 inflammation (at least 15 eosinophils/high power field) when other secondary systemic and local causes of esophageal eosinophilia are excluded. Although this disease was initially ascribed to a delayed reaction to food allergens, emerging evidence suggests that aeroallergens may also play a role in pathogenesis and disease course. Some studies support seasonal variations in the diagnosis of eosinophilic esophagitis and disease exacerbations owing to the increase in aeroallergens to which patients are sensitized. It is also known that this disease can be caused by extensive, identifiable exposure to aeroallergens and after treatment with specific immunotherapy based on food or aeroallergens. It was recently postulated that treatment of allergic rhinoconjunctivitis can improve the symptoms of eosinophilic esophagitis, although data are limited to case reports and small series. Currently, biomarkers and biologic therapies are not helpful for diagnosis or inducing clinical and histological remission of the disease. Nevertheless, there are high hopes for dupilumab. This review aims to give visibility to the involvement of aeroallergens in the triggering and exacerbation of eosinophilic esophagitis, since many of them, in addition to being airborne and inhalant, can also be ingested as food. Clearly, we must try to identify the cause of the disease to ensure remission.
Topics: Humans; Eosinophilic Esophagitis; Allergens; Food Hypersensitivity; Eosinophils; Disease Progression
PubMed: 36000828
DOI: 10.18176/jiaci.0853 -
Clinical and Translational Allergy 2019Double-blind, placebo-controlled trials (DBPCTs) have confirmed the efficacy of allergen-specific immunotherapy (AIT) with depigmented-polymerized allergen extracts... (Review)
Review
BACKGROUND
Double-blind, placebo-controlled trials (DBPCTs) have confirmed the efficacy of allergen-specific immunotherapy (AIT) with depigmented-polymerized allergen extracts (DPAEs). This systematic review evaluates the efficacy of AIT using different allergens in different severity stages of rhinoconjunctivitis with or without asthma in the pollen studies and asthma and rhinitis in the house dust mite studies in comparison to placebo.
METHODS
We used MEDLINE, Embase, CENTRAL and LILACS databases to review DBPCTs published until July 2016. The combined symptom and medication score (cSMS) served as primary endpoint. The total rhinoconjunctivitis symptom score (RCSS) and total score in Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) were secondary efficacy endpoints. Solicited local and systemic adverse events were secondary safety endpoints. We assumed a random effects model with standardized mean differences (SMDs) or mean differences as summary statistics. In a subgroup analysis, we classified the studies following the GINA (Global Initiative for Asthma) and ARIA (Allergic Rhinitis and its Impact on Asthma) guidelines for rhinoconjunctivitis and asthma severity.
RESULTS
Six DBPCTs in pollen and 2 trials in house dust mites (HDM) were selected. Patients (N = 915) with intermittent or mild persistent asthma were included in 3 (37.5%) and 5 (62.5%) trials, respectively. Two (25%) HDM studies included patients with moderate persistent asthma, 4 trials patients with moderate-to-severe rhinoconjunctivitis. Treatment periods ranged from 12 to 24 months. AIT with DPAEs yielded significantly lower cSMS (SMD: 1.9, 95% CI: 0.9-2.8) and RQLQ (SMD: 0.3, 95% CI: 0.1-0.5) values than did placebo. An exploratory analysis of cSMS and RCSS suggested that the efficacy of AIT treatment with DPAEs was higher in trials including patients with more severe rhinoconjunctivitis and asthma. A publication bias was not detected. Heterogeneity between individual studies was explained by differences in severity. Patients receiving DPAEs did not experience a significantly higher risk of local (OR: 1.55, 95% CI: 0.86-2.79) or systemic reactions (OR: 1.94, 95% CI: 0.98-3.84).
CONCLUSIONS
Compared to placebo, AIT with DPAEs is effective in patients with pollen- or HDM-induced rhinoconjunctivitis with or without allergic asthma and improves health-related quality of life. It does not differ significantly in safety and tolerability.
PubMed: 31171962
DOI: 10.1186/s13601-019-0268-5