[Component-resolved diagnosis of tree pollen allergen: identify key allergens to develop treatment plans].

With the increasing global prevalence of tree pollen allergies, there has been a significant impact on the quality of life for populations. In North and Central China, birch pollen, cypress pollen, and plane tree pollen are the most common allergens for springtime pollen allergy sufferers. The distribution of plants and patterns of pollen transmission in different geographical areas result in varying pollen exposure outcomes, further complicating the challenges in diagnosis and individualized treatment. This article delves into the research progress and clinical application of tree pollen allergies based on the "Molecular Allergology User's Guide 2.0 (MAUG 2.0) " published by the European Academy of Allergy and Clinical Immunology (EAACI). It discusses major allergen families and component proteins of tree pollen such as PR-10 proteins, profilins, polcalcins, as well as cross-reactive components that may cause pollen-food allergy syndrome. Allergen component diagnostics can distinguish true allergy sufferers from those with multiple allergen reactions, enabling more targeted selection of allergens for specific immunotherapy, thus enhancing treatment effectiveness. Bet v 1 and Cup a 1, for instance, are specific indicators for immunotherapy in birch and cypress allergy patients. Overall, this article provides cutting-edge information for professionals in the field of tree pollen allergies, offering in-depth exploration of tree pollen allergen component proteins, clinical manifestations, and treatment-related research, aiding in better understanding and addressing the challenges of tree pollen allergies.

Heterogeneity of sensitization profiles and clinical phenotypes among patients with seasonal allergic rhinitis in Southern European countries-The @IT.2020 multicenter study.

BACKGROUND: Pollen allergy poses a significant health and economic burden in Europe. Disease patterns are relatively homogeneous within Central and Northern European countries. However, no study broadly assessed the features of seasonal allergic rhinitis (SAR) across different Southern European countries with a standardized approach. OBJECTIVE: To describe sensitization profiles and clinical phenotypes of pollen allergic patients in nine Southern European cities with a uniform methodological approach. METHODS: Within the @IT.2020 multicenter observational study, pediatric and adult patients suffering from SAR were recruited in nine urban study centers located in seven countries. Clinical questionnaires, skin prick tests (SPT) and specific IgE (sIgE) tests with a customized multiplex assay (Euroimmun Labordiagnostika, Lübeck, Germany) were performed. RESULTS: Three hundred forty-eight children (mean age 13.1 years, SD: 2.4 years) and 467 adults (mean age 35.7 years SD: 10.0 years) with a predominantly moderate to severe, persistent phenotype of SAR were recruited. Grass pollen major allergenic molecules (Phl p 1 and/or Phl p 5) ranged among the top three sensitizers in all study centers. Sensitization profiles were very heterogeneous, considering that patients in Rome were highly poly-sensitized (sIgE to 3.8 major allergenic molecules per patient), while mono-sensitization was prominent and heterogeneous in other cities, such as Marseille (sIgE to Cup a 1: n = 55/80, 68.8%) and Messina (sIgE to Par j 2: n = 47/82, 57.3%). Co-sensitization to perennial allergens, as well as allergic comorbidities also broadly varied between study centers. CONCLUSIONS: In Southern European countries, pollen allergy is heterogeneous in terms of sensitization profiles and clinical manifestations. Despite the complexity, a unique molecular, multiplex, and customized in-vitro IgE test detected relevant sensitization in all study centers. Nevertheless, this geographical diversity in pollen allergic patients imposes localized clinical guidelines and study protocols for clinical trials of SAR in this climatically complex region.

Identification of Pla a 7 as a novel pollen allergen group in Platanus acerifolia pollen.

BACKGROUND: Platanus acerifolia is recognized as a source of allergenic pollen worldwide. Currently, five Platanus acerifolia pollen allergens belonging to different protein families have been identified, in which profilin and enolase were characterized by our group recently. Besides, we also screened and identified a novel allergen candidate as triosephosphate isomerase, which was different from already known types of pollen allergens. However, the role of this novel allergen group in Platanus acerifolia pollen allergy was unclear. Therefore, we further investigated the allergenicity and clarify its clinical relevance in this study. METHODS: The natural triosephosphate isomerase from Platanus acerifolia pollen was purified by three steps of chromatography and identified by mass spectrometry. The cDNA sequence of this protein was matched from in-house transcripts based on internal peptide sequences, which was further confirmed by PCR cloning. The recombinant triosephosphate isomerase was expressed and purified from E. coli. Allergenicity analysis of this protein was carried out by enzyme linked immunosorbent assay, immunoblot, and basophil activation test. RESULTS: A novel allergen group belonging to triosephosphate isomerase was firstly identified in Platanus acerifolia pollen and named as Pla a 7. The cDNA of Pla a 7 contained an open reading frame of 762 bp encoding 253 amino acids. The natural Pla a 7 displayed 41.4% IgE reactivity with the patients' sera by ELISA, in which the absorbance value showed correlation to the serum sIgE against Platanus acerifolia pollen extract. Inhibition of IgE-binding to pollen extracts reached 26%-94% in different Pla a 7-positive sera. The recombinant Pla a 7 exhibited weaker IgE-reactivity in ELISA than its natural form, but showed comparable activity in immunoblot. The allergenicity was further confirmed by basophil activation test. CONCLUSIONS: Triosephosphate isomerase (Pla a 7) was first recognized as pollen allergen in Platanus acerifolia pollen, which is a completely different type of pollen allergen from those previously reported. This finding is essential to enrich information on allergen components and pave the way for molecular diagnosis or treatment strategies for Platanus acerifolia pollen allergy.

A Pilot Study to Identify Grass Species That Mediate Pollen Allergy in Thailand.

INTRODUCTION: Some grass species that are either common or widely spread in Thailand have not been used for pollen allergy diagnosis. In order to improve diagnostic accuracy, the aim of this pilot study was to identify the grass species responsible for pollen allergy in Thailand. METHODS: The skin sensitization of pollen extracts from six different grass species, including rice (Oryza sativa), corn (Zea mays), sorghum (Sorghum bicolor), para grass (Urochloa mutica), ruzi grass (Urochloa eminii), and green panic grass (Megathyrsus maximus), was evaluated by skin prick test (SPT). Serum's IgE specific to each pollen extract was analyzed by Western blot (WB). The ImmunoCAPTM test for Johnson grass was also evaluated. RESULTS: Of the thirty-six volunteers who participated in this study, eighteen tested positive for at least one of the diagnostic tests, namely SPT, WB analysis, or ImmunoCAPTM. Notably, skin reactivity to para grass, corn, sorghum, and rice was more commonly observed compared to ruzi grass and green panic grass. However, in the WB analysis, individuals with pollen-specific IgE were more frequently detected in sorghum, green panic grass, corn, rice, and ruzi grass than para grass. CONCLUSION: In this pilot investigation, our findings indicate that the pollen extracts of rice, corn, sorghum, and para grass are associated with pollen allergy in Thailand. These results contribute to the current knowledge on the identification of grass species that are associated with pollen allergy in Thailand and Southeast Asia.

The "allergic nose as a pollen detector" concept: e-Diaries to predict pollen trends.

Hirst pollen traps and operator pollen recognition are worldwide used by aerobiologists, providing essential services for the diagnosis and monitoring of allergic patients. More recently, semiautomated or fully automated detector systems have been developed, which facilitate prediction of pollen exposure and risk for the individual patient. In parallel, smartphone apps consisting of short questionnaires filled in daily by the patient/user provide daily scores, time trajectories, and descriptive reports of the severity of respiratory allergies in patients with pollen allergy. The usual scientific and clinical approach to this matter is to monitor the environment (pollen concentration) in order to predict the risk of symptoms (allergic rhinitis) in a population. We discuss here the opposite, contraintuitive possibility, that is, the use of e-diaries to collect daily information of mono-sensitized pollen-allergic patients in order to predict the clinically efficient airborne exposure to a given pollen, area, and time period. In line with the "Patient as Sensor" concept, proposed in 2013 by Bernd Resch, the "allergic nose" may be used as a pollen detector in addition to existing calibrated hardware sensors, namely the pollen stations, thus contributing with individual measurements, sensations, and symptoms' perception. The target of this review is to present a novel concept of pollen monitoring based on "pollen-detector" patients to inspire future cooperative studies aimed at investigating and hopefully validating our hypothesis.

Intralymphatic immunotherapy with birch and grass pollen extracts. A randomized double-blind placebo-controlled clinical trial.

INTRODUCTION: There is a need to evaluate the safety and efficacy of intralymphatic immunotherapy (ILIT) for inducing tolerance in patients with allergic rhinitis. METHODS: Thirty-seven patients with seasonal allergic symptoms to birch and grass pollen and skin prick test >3 mm and/or IgE to birch and timothy >0.35 kU/L were randomized to either ILIT, with three doses of 0.1 mL of birch pollen and 5-grass pollen allergen extracts on aluminium hydroxide (10,000 SQ-U/ml; ALK-Abelló) or placebo using ultrasound-guided intralymphatic injections at monthly intervals. Daily combined symptom medical score and rhinoconjunctivitis total symptom score were recorded during the peak pollen seasons the year before and after treatment. Rhinoconjunctivitis total symptom score, medication score and rhinoconjunctivitis quality of life questionnaire were recorded annually starting 2 years after treatment. Circulating proportions of T helper cell subsets and allergen-induced cytokine and chemokine production were analysed using flow cytometry and ELISA. RESULTS: There were no differences between the groups related to daily combined symptom medical score the year before and after treatment. Two years after ILIT (after unblinding), the actively treated group reported significantly fewer symptoms, lower medication use and improved quality of life than did the placebo group. After the pollen seasons the year after ILIT, T regulatory cell frequencies and grass-induced IFN-γ levels increased only in the actively treated group. CONCLUSION: In this randomized controlled trial, ILIT with birch and grass pollen extract was safe and accompanied by immunological changes. Further studies are required to confirm or refute the efficacy of the treatment.

[Research progress of oral allergy syndrome].

Oral allergy syndrome (OAS) is an IgE-mediated hypersensitivity. Patients with pollen allergy will experience oropharyngeal allergy after eating fresh fruits or vegetables containing homologous pathogenesis-related allergen, occasionally accompanied by systemic symptoms, it is a special type of food hypersensitivity in which respiratory allergens and food allergens are similar structurally and lead to the cross-reactivity. At present, there is little research and attention to it in China. To master the definition, epidemiological characteristics, pathological mechanism, diagnosis, prevention and treatment of OAS is very important to the prevention and control of OAS. This article reviews the research progress of OAS, providing reference and prevention basis for clinicians to improve the diagnosis and differential diagnosis of OAS.

Skin Physiology, Mucosal Functions, and Symptoms Are Modulated by Grass Pollen and Ozone Double Exposure in Allergic Patients.

INTRODUCTION: Along with climate changes, we see an increase in allergic symptoms and the number of pollen-allergic patients in many countries. Increased allergic symptoms are associated with an elevated ozone exposure which may be linked by impaired epithelial barrier function. This study aimed to quantify the clinical effect of ozone and pollen double exposure (DE). We tested whether ozone impairs barrier-related skin physiology and mucosal functions under DE with pollen in grass pollen-allergic patients versus healthy controls. METHODS: This case-control study included 8 grass pollen-allergic patients and 8 non-allergic healthy subjects exposed to grass pollen and ozone in the GA2LEN pollen chamber, comparing shorter and longer DE duration. Non-invasive skin physiological parameters were assessed, including stratum corneum hydration, skin redness, surface pH, and basal transepidermal water loss as a parameter for epidermal barrier function. The subjects' general well-being, bronchial, nasal, and ocular symptoms were documented. RESULTS: Skin physiology tests revealed that DE in allergic patients deteriorates the epidermal barrier function and increases the surface pH and skin redness. DE significantly induced nasal secretion in pollen-allergic versus healthy subjects, which was more pronounced with longer DE. The general well-being was significantly impaired under DE versus pollen or ozone alone, with a negative influence of DE duration. No relevant bronchial symptoms were recorded. CONCLUSION: Skin physiology and nasal mucosal symptoms are negatively affected by ozone and grass pollen DE in allergic patients. The negative effects showed, in some parameters, a dose (time)-response relationship. The pH can be regarded as a possible modulatory mechanism.

A comparison of experience sampled hay fever symptom severity across rural and urban areas of the UK.

Hay fever affects people differently and can change over a lifetime, but data is lacking on how environmental factors may influence this. This study is the first to combine atmospheric sensor data with real-time, geo-positioned hay fever symptom reports to examine the relationship between symptom severity and air quality, weather and land use. We study 36145 symptom reports submitted over 5 years by over 700 UK residents using a mobile application. Scores were recorded for nose, eyes and breathing. Symptom reports are labelled as urban or rural using land-use data from the UK's Office for National Statistics. Reports are compared with AURN network pollution measurements and pollen and meteorological data taken from the UK Met Office. Our analysis suggests urban areas record significantly higher symptom severity for all years except 2017. Rural areas do not record significantly higher symptom severity in any year. Additionally, symptom severity correlates with more air quality markers in urban areas than rural areas, indicating that differences in allergy symptoms may be due to variations in the levels of pollutants, pollen counts and seasonality across land-use types. The results suggest that a relationship exists between urban surroundings and hay fever symptoms.

Prevalence and clinical features of pollen-food allergy syndrome in adults with seasonal allergic rhinitis.

OBJECTIVE: Pollen-food allergy syndrome (PFAS) is an IgE-mediated allergic reaction to certain foods due to prior sensitization to pollen allergens. The data about the prevalence of PFAS in adults in Turkey is not sufficiently reported. Our objective was to investigate the frequency and clinical features of PFAS in adult patients with seasonal allergic rhinitis (SAR). PATIENTS AND METHODS: A total of 222 patients with SAR were enrolled in our outpatient allergy clinic at Hacettepe University, during a ten-month period. A questionnaire was used to evaluate patients and to categorize those who experienced obvious allergy symptoms consistent with PFAS. Atopy was assessed by a standard skin prick test panel including common aeroallergen extracts. RESULTS: Among 222 patients with a diagnosis of SAR, 31 had patient reported PFAS (31/222, 14%). Among them, 23 (74.2%) were females, and their mean age was 32.29±9.24 years. The most common symptoms were isolated oropharyngeal symptoms (58.1%), followed by urticaria (51.6%) after culprit food ingestion. The most frequent culprit foods were eggplant, walnut, kiwi, peach, and melon. The predominant sensitizing aeroallergen was grass pollen. CONCLUSIONS: PFAS can be frequently observed in adults who are followed up for SAR. The most frequently involved foods are eggplant, walnut, kiwi, peach, and melon in Ankara Province. The symptoms of PFAS are usually localized in the oropharyngeal area and are self-limited.

Extract-Shaped Immune Repertoires as Source for Nanobody-Based Human IgE in Grass Pollen Allergy.

The presence of allergen-specific IgE in serum is a biomarker for allergic disease. Specific IgE antibodies for research and diagnostics, however, remain scarce. In contrast to prototypic antibodies, camelid species have evolved single domains as moiety for antigen recognition. These so-called nanobodies represent a versatile platform for the development of diagnostic and therapeutic approaches. In this study, we aimed for generating nanobodies and derived IgE formats from an extract-shaped immune repertoire. Timothy grass pollen represents a complex, but well-defined mixture of individual allergens. Therefore, a repertoire library from a timothy grass pollen extract immunised llama was established. The selection by phage display yielded 3 nanobodies with immunoreactivity to the extract. IgE-like nanobody-based human IgE (nb-hIgE) antibodies were produced in mammalian cells and assessed in different immunoassays and commercial platforms. Immunoblotting and diagnostic ImmunoCap analysis of single timothy grass pollen allergens identified the major allergens Phl p 6 and Phl p 4 as targets. Assessment of immunoreactivity further documented significant molecular cross-reactivity with pollen extract of different grass species and variant presence of allergens within extracts of Pooideae grasses. In summary, our study shows that extract-based immunisation enables the generation of allergen-specific nanobodies and derived nb-hIgE formats linking nanobody technologies with allergological applications.

Assessment of Co-Sensitization between Pollen and Food Allergen Sources among Bengali Population, West Bengal, India.

INTRODUCTION: Secondary food allergies due to cross-reactivity between pollen and food allergens are a significant health burden in India. Prevalence of cross-reactivity varies by region, and particularly in West Bengal, it remains unexplored. The present study investigated sensitivities of pollen-related food allergy (PFA) patients of West Bengal by empirically determining co-sensitization patterns. METHODS: The present study retrospectively analysed 1,310 pollen-allergic (PA) patients from the Allergy and Asthma Research Centre, West Bengal. A questionnaire survey was performed to record patients' demographic and clinical features and categorized into seasonal and perennial ones. All patients were subjected to the skin prick test and specific IgE for evaluation of sensitivity against 16 pollen and 16 food allergens. Co-relation and principal component analysis (PCA) was performed to determine co-sensitivity. RESULTS: Seasonal allergic patients were comparatively higher than perennial ones. PFA patients were mostly sensitive to eggplant (n = 387), while Azadirachta indica (n = 341) was predominant sensitizer among pollen allergen sources. Cynodon dactylon showed maximum significant positive correlation with banana, orange, peanut, pineapple, cucumber, eggplant, potato, tomato, and wheat. In the seasonal group, Cynodon dactylon-specific IgE in PFA patients (median = 4.60 kU/L) was significantly higher from that of PA ones (median = 3.44 kU/L). Among 32 allergens tested, 27 were placed in first two dimensions of the PCA biplot. CONCLUSION: The present study established that co-sensitivity between pollen and food allergen sources were predominant in allergic patients of West Bengal. The co-sensitization patterns among unrelated allergen sources may be due to possible expression of biologic cross-reactivity to similar allergens.

RNA sequencing of single allergen-specific memory B cells after grass pollen immunotherapy: Two unique cell fates and CD29 as a biomarker for treatment effect.

BACKGROUND: Sublingual immunotherapy (SLIT) for grass pollen allergy can modify the natural history of allergic rhinitis and is associated with increased allergen-specific IgG4 . IgG4 competitively inhibits functional IgE on the surface of effector cells, such as mast cells and basophils, from binding to allergens. To further understand the important role memory B-cell (Bmem) responses play in mediating the beneficial effects of SLIT, we assessed changes in allergen-specific Bmem subsets induced by SLIT for grass pollen allergy. METHODS: Blood samples were collected twice outside the pollen season from twenty-seven patients with sensitization to ryegrass pollen (RGP; Lolium perenne) and seasonal rhinoconjunctivitis. Thirteen received 4-month pre-seasonal SLIT for grass pollen allergy, and 14 received standard pharmacotherapy only. Single-cell RNA sequencing was performed on FACS-purified Lol p 1-specific Bmem before and after SLIT from four patients, and significant genes were validated by flow cytometry on the total cohort. RESULTS: Four months of SLIT increased RGP-specific IgE and IgG4 in serum and induced two Lol p 1-specific Bmem subsets with unique transcriptional profiles. Both subsets had upregulated expression of beta 1 integrin ITGB1 (CD29), whereas IGHE (IgE), IGHG4 (IgG4 ), FCER2 (CD23), and IL13RA1 were upregulated in one subset. There was an increase in the proportion of Lol p 1+ Bmem expressing surface IgG4 , CD23, and CD29 after SLIT. CONCLUSIONS: A clinically successful 4 months course of SLIT for grass pollen allergy induces two transcriptionally unique Bmem fates. Associated changes in surface-expressed proteins on these Bmem subsets can be used as early biomarkers for treatment effects.

Granos de polen anemófilos: sensibilización en pacientes alérgicos / Anemophilic pollen grains: sensitization in allergic patients

A nivel mundial, los aeroalérgenos más frecuentes causantes de enfermedades alérgicas son los granos de polen anemófilos. Estos han sido capaces de desencadenar crisis que han reflejado una elevada morbilidad. En Cuba los estudios de sensibilización a granos de polen han sido escasos. Con el objetivo de determinar la sensibilización a granos de polen en pacientes alérgicos y su relación con la presencia de enfermedades alérgicas, se realizó un estudio observacional descriptivo de corte transversal, no aleatorizado, de marzo a junio del 2019. La muestra se constituyó de 33 pacientes con asma, rinitis, rinoconjuntivitis alérgica, dermatitis atópica y conjuntivitis alérgica. A todos los pacientes se les realizó historia clínica alergológica y prueba cutánea por punción con extractos alergénicos de: Helianthus annus, Cosmos bipinnatus, Cynodon dactylon, Quercus sp, Eucaliptus sp. Se aplicaron las frecuencias absolutas, porcientos, desviación estándar, promedio, edad media y test de Spearman para su análisis. La edad media de la muestra fue de 36,9 años, con predominio de mujeres. Más del 50por ciento de los pacientes presentaron sensibilización a granos de polen; y de ellos, el 24,24por ciento resultaron polisensibilizados. El mayor porcentaje de sensibilización fue a Cynodon dactylon. La rinitis alérgica fue la enfermedad que prevaleció en la población estudiada(AU)

Nowadays, the most frequent aeroallergens causing allergy diseases have been anemophilous pollen grains. They have been able to triggers crises that have reflected a high morbidity. In Cuba, studies of sensitization to pollen grains have been scarce. The objective of our research was to determine the sensitization to pollen grains in allergic patients and its relationship with the presence of allergic diseases. A non-randomized, descriptive, cross-sectional, observational study was conducted from March to June 2019. The sample consisted of 33 patients with asthma, allergic rhinitis, rhinoconjunctivitis, atopic dermatitis and allergic conjunctivitis. All patients underwent allergic history and skin prick test testing with allergenic extracts of: Helianthus annus, Cosmos bipinnatus, Cynodon dactylon, Quercus sp, Eucalyptus sp. Absolute frequencies, percentages, standard deviation, mean, average age, and Spearman´s test were applied for analysis. The average age of the sample was 36.9 years, with a predominance of women. More than 50percent of the patients presented sensitization to pollen grains; of them, 24.24percent polysensitized. The highest percentage of sensitization was to Cynodon dactylon. Allergic rhinitis was the disease that prevailed in the population studied(AU)

[Expert consensus on diagnosis, treatment and prevention of allergic diseases(Part â ¢)].

As the third part of the expert consensus on allergic diseases, this article includes efficacy evaluation, characteristics of allergic diseases in special populations, social and economic burden, psychological problems and prevention. The efficacy evaluation methods include symptom score, quality of life score and drug score. Allergic diseases of special populations have unique clinical characteristics and need special attention. The social and economic burden of allergic diseases is becoming heavier, which requires more attention. The three-level prevention of pollinosis can be completed through the "five in one" prevention and control strategies such as local vegetation survey, airborne pollen monitoring, epidemiological survey, standardized training of grassroots medical personnel, science popularization and academic lectures, which is more comprehensive and perfect than the "four in one" treatment strategy.

Homeopathy for seasonal allergic rhinitis: rationale, design and methods of the three-armed randomized controlled HOMEOSAR trial.

BACKGROUND: Patients with seasonal allergic rhinitis (SAR) frequently use homeopathic therapy. Although there is some evidence that homeopathy may be effective in treating symptoms of SAR, there is a lack of high-quality clinical trials. Therefore, the aim of the homeopathy for SAR (HOMEOSAR) trial is to determine the efficacy of individualized or standardized homeopathic drug treatment compared to placebo regarding rhinitis-related quality of life in patients with SAR. METHODS: This randomized, placebo-controlled, double-blind, three-armed intervention study will be conducted at two university hospital outpatient clinics for complementary and integrative medicine in Berlin and in 12 office-based practices specializing in homeopathic treatment in Germany. A total of 270 patients with clinical symptoms of SAR and positive allergy test to birch and grass pollen will receive homeopathic anamnesis and subsequently be randomized into (a) standardized homeopathic drug treatment with Galphimia Glauca (potency D6), (b) individualized homeopathic drug treatment (D6), or (c) placebo. All three groups can receive on-demand rescue medication as needed. Treatment will consist of two consultations and daily intake of the study medication for 4 weeks during the pollen season. The primary outcome is the mean overall score of the Rhinitis Quality of Life Questionnaire (RQLQ) in weeks 3 and 4, analyzed using analysis of covariance (adjusted for baseline RQLQ overall score and study center). A closed testing procedure will be used to control the overall type I error comparing the 3 treatment groups. Secondary outcomes include the overall RQLQ and its seven domain scores, responder status (decrease in RQLQ overall score of at least 0.5 points compared to the baseline value), use of rescue medication, intensity of total and individual SAR symptoms based on visual analog scale, generic health-related quality of life, safety, utilization of health care resources and associated costs. In addition, a qualitative data analysis is planned. CONCLUSION: The results of our study will contribute to clarifying the possible therapeutic effects of homeopathic drug treatment for patients with SAR. TRIAL REGISTRATION: This study has been registered in the German Clinical Trial Registry with trial ID DRKS00018081 on June 09, 2020.

Pollen sensitization among Egyptian patients with respiratory allergic diseases.

Pollen is responsible for seasonal allergies, such as allergic rhino-conjunctivitis (AR), and has become a growing public health concern. Climate change affects the range of allergenic species as well as the timing and length of the pollen season. In Egypt, data on pollinosis are scarce. This study aimed to identify the most prevalent pollen causing allergies among Egyptian patients with respiratory allergies. A total of 200 patients with respiratory allergic diseases, allergic rhinitis and/or bronchial asthma (BA), were included. Medical history taking and physical examinations were conducted on each patient. Complete blood count (CBC), total immunoglobulin E (IgE) determination, spirometry, specific IgE, and skin prick tests (SPTs) for common aeroallergens and food were performed. Of the 200 patients, 106 (53%) were females. The age of study subjects ranged 16-66 years (mean ± SD, 34.42 ± 13.0), and 65% were living in urban areas. Grass pollen, mainly from Timothy grass and maize, were the most prevalent allergens (28.5%). Timothy grass was the most common type of pollen in patients with AR (28.3 %). Elder pollen was more prevalent among asthmatic patients (P = 0.004). Bermuda grass was statistically more prevalent in rural than in urban areas (P = 0.008). Maize was linked to uncontrolled BA, whereas Timothy grass was the most prevalent among patients with moderate/severe AR. Forty-three patients had oral allergy syndrome; oranges and tomatoes were the most cross-reactive food allergies (12% and 11.5%, respectively). Exacerbation of allergic symptoms was noted during January, December, March, and June. In conclusion, pollen plays a substantial role in affecting patients with respiratory allergies in Egypt. Grass pollen is the most prevalent type of pollen, especially in urban areas.