[Oral allergy syndrome (OAS)]. / Síndrome polen-alimento (síndrome de alergia por vía oral).

The pollen-food allergy syndrome, also known as oral allergy syndrome, is characterized by local reactions in the mouth and throat after consuming certain raw plant foods in individuals sensitized to pollen from grass, weeds, and trees. Birch-apple is the prototype of this syndrome, with apple, pear, and plum being the most commonly associated foods. Symptoms are usually limited to the oral cavity but can include systemic reactions, including anaphylaxis. Sensitization to pollen allergens, such as lipid transfer proteins, profilin, and PR-10 proteins, triggers this syndrome. Its prevalence varies by geographic region and the predominant pollen type, affecting between 30% and 60% of food allergies. Diagnosis involves a clinical history, skin tests, and, in ambiguous cases, double-blind, placebo-controlled oral food challenges. Treatment primarily involves avoiding trigger foods.

El síndrome de alergia a alimentos y pólenes, también conocido como síndrome polen-alimento o síndrome de alergia oral, se caracteriza por una reacción local en la boca y faringe después de ingerir ciertos alimentos vegetales crudos, en individuos sensibilizados al polen de hierbas, malezas y árboles. El abedul-manzana es el prototipo de este síndrome, siendo la manzana, pera y ciruela los alimentos más comúnmente asociados. Los síntomas suelen limitarse a la cavidad oral, pero pueden incluir reacciones sistémicas, incluida la anafilaxia. La sensibilización a alérgenos de polen, como las proteínas de transferencia de lípidos, profilina y proteínas PR-10, desencadena este síndrome. Su prevalencia varía según la región geográfica y el tipo de polen predominante, afectando entre el 30% y el 60% de las alergias alimentarias. El diagnóstico implica historia clínica, pruebas cutáneas y, en casos ambiguos, pruebas de provocación alimentaria oral. El tratamiento consiste principalmente en evitar los alimentos desencadenantes.

Birch Pollen Allergens.

Birch belongs to the order Fagales and the family Betulaceae. Birch pollen is one of the most important airborne inhaled allergens in the north temperate zone, leading to allergic rhinitis, asthma and pollen-related food allergy. The sensitization rate to birch pollen is about 8-16% in the general population and 7-57% in patients seen at various allergy centers. Seven birch pollen allergens have been recognized by the International Allergen Nomenclature Sub-committee, with Bet v 1 as the sole major allergen. Component-resolved diagnostics can help to discriminate broad cross-reactivity and false-positive diagnoses of pollen allergy caused by specific IgE to pan-allergens such as Bet v 2, 4 or Bet v 7 from true birch allergy represented by the major allergen Bet v 1-specific IgE. Patients with allergic symptoms to birch pollen showed significantly higher serum anti-Bet v 1 IgE concentrations than asymptomatic individuals with birch sensitization. A higher level of IgE to Bet v 1 also predicted oral allergy syndrome after the ingestion of Rosaceae fruits, nuts, or Apiaceae vegetables, which have cross-reactive homologous allergens with birch allergens. Bet v 1 is one of the first allergens developed using recombinant technology. Many forms of genetically modified Bet v 1 hypo-allergens have been developed and have shown benefit in animal models or even clinical trials of allergen immunotherapy.

Development of mouse model for oral allergy syndrome to identify IgE cross-reactive pollen and food allergens: ragweed pollen cross-reacts with fennel and black pepper.

Oral allergy syndrome (OAS) is an IgE-mediated immediate food allergy that is localized to the oral mucosa. Pollen food allergy syndrome (PFAS), a pollinosis-associated OAS, is caused by cross-reactivity between food and pollen allergens. However, we need to more precisely understand the underlying pathogenesis of OAS/PFAS. In the present study, we developed a method to comprehensively identify cross-reactive allergens by using murine model of OAS and protein microarray technology. We focused on lip angioedema, which is one of the most common symptoms of OAS, and confirmed that mast cells reside in the tissues inside the lower lip of the mice. Interestingly, when the food allergen ovalbumin (OVA) was injected inside the lower lip of mice with high levels of OVA-specific IgE followed by an intravenous injection of the Evans blue dye, we found immediate dye extravasation in the skin of the neck in a mast cell-dependent manner. In addition, the degree of mast cell degranulation in the oral cavity, reflecting the severity of oral allergic responses, can be estimated by measuring the amount of extravasated dye in the skin. Therefore, we used this model of OAS to examine IgE cross-reactive allergens in vivo. Protein microarray analysis showed that serum IgE from mice intraperitoneally sensitized with ragweed pollen, one of the major pollens causing pollinosis, bound highly to protein extracts from several edible plants including black peppercorn and fennel. We confirmed that the levels of black pepper-specific IgE and fennel-specific IgE were significantly higher in the serum from ragweed pollen-sensitized mice than in the serum from non-sensitized control mice. Importantly, analysis of murine model of OAS showed that the injection of black pepper or fennel extract induced apparent oral allergic responses in ragweed pollen-sensitized mice. These results indicate IgE cross-reactivity of ragweed pollen with black pepper and fennel. In conclusion, we developed mouse model of OAS to identify IgE cross-reactive pollen and food allergens, which will help understand the pathogenesis of OAS/PFAS.

BSACI guideline for the diagnosis and management of pollen food syndrome in the UK.

Pollen food syndrome (PFS) is a highly prevalent food allergy affecting pollen-sensitized children and adults. Sufferers experience allergic symptoms when consuming raw plant foods, due to the homology between the pollen allergens and unstable proteins in these foods. The triggers involved can vary depending on the pollen sensitization, which in turn is affected by geographical location. The British Society of Allergy and Clinical Immunology (BSACI) Standards of Care Committee (SOCC) identified a need to develop a guideline for the diagnosis and management of PFS in the United Kingdom (UK). Guidelines produced by the BSACI use either the GRADE or SIGN methodology; due to a lack of high-quality evidence these recommendations were formulated using the SIGN guidelines, which is acknowledged to be less robust than the GRADE approach. The correct diagnosis of PFS ensures the avoidance of a misdiagnosis of a primary peanut or tree nut allergy or confusion with another plant food allergy to non-specific lipid transfer proteins. The characteristic foods involved, and rapid-onset oropharyngeal symptoms, mean PFS can often be diagnosed from the clinical history alone. However, reactions involving tree nuts, peanuts and soya milk or severe/atypical reactions to fruits and vegetables may require additional diagnostic tests. Management is through the exclusion of known trigger foods, which may appear to be simple, but is highly problematic if coupled with a pre-existing food allergy or for individuals following a vegetarian/vegan diet. Immunotherapy to pollens is not an effective treatment for PFS, and although oral or sublingual immunotherapy to foods seems more promising, large, controlled studies are needed. The typically mild symptoms of PFS can lead to an erroneous perception that this condition is always easily managed, but severe reactions can occur, and anxiety about the onset of symptoms to new foods can have a profound effect on quality of life.

Homemade Food Allergen Extracts for Use in Skin Prick Tests in the Diagnosis of IgE-Mediated Food Allergy: A Good Alternative in the Absence of Commercially Available Extracts?

INTRODUCTION: The skin prick test (SPT) is the first step in the diagnosis of an immunoglobulin E (IgE)-mediated food allergy. The availability of commercial food allergen extracts is very limited, resulting in a need for alternative extraction methods of food allergens. The objective of this study was to compare the SPT results of homemade food allergen extracts with commercially available extracts. METHODS: Adult patients with a suspected food allergy were included. Food allergen-specific symptoms were scored using a questionnaire. SPTs were performed with homemade and commercially available extracts (ALK-Abelló, Kopenhagen, Denmark) from almond, apple, hazelnut, peach, peanut, and walnut. Serum-specific IgE was measured with ISAC or ImmunoCAP™. Intra-class correlation coefficients (ICC) between the SPT results of both extract methods were calculated. The proportion of agreement with food allergen-specific symptoms was analyzed. RESULTS: Fifty-four patients (mean age 36; range 19-69 years; female/male: 42/12) were included. The intra-class correlation coefficient (ICC) between the SPT results of both extract methods were strong for hazelnut 0.79 (n = 44) and walnut 0.78 (n = 31), moderate for apple 0.74 (n = 21) and peanut 0.66 (n = 28), and weak for almond 0.36 (n = 27) and peach 0.17 (n = 23). The proportion of agreement between SPT results and food allergen-specific symptoms was comparable for homemade and commercially available extracts, except for peach; 0.77 versus 0.36, respectively. CONCLUSION: In the diagnostic procedures to identify an IgE-mediated food allergy, homemade extracts from hazelnut and walnut appear to be a good alternative in the absence of commercially available food allergen extracts.

Heterogeneity of pollen food allergy syndrome in seven Southern European countries: The @IT.2020 multicenter study.

BACKGROUND: Pollen food allergy syndrome (PFAS) is a frequently underdiagnosed disease due to diverse triggers, clinical presentations, and test results. This is especially relevant in geographic areas with a broad spectrum of pollen sensitization, such as Southern Europe. OBJECTIVES: To elucidate similarities and differences of PFAS in nine Southern European centers and identify associated characteristics and unique markers of PFAS. METHODS: As part of the @IT.2020 Multicenter Study, 815 patients with seasonal allergic rhinitis (SAR), aged 10-60 years, were recruited in seven countries. They completed questionnaires regarding SAR, comorbidities, family history, and PFAS, and underwent skin prick testing (SPT) and serum IgE testing. RESULTS: Of the 815 patients, 167 (20.5%) reported PFAS reactions. Most commonly, eliciting foods were kiwi (58, 34.7%), peach (43, 25.7%), and melon (26, 15.6%). Reported reactions were mostly local (216/319, 67.7%), occurring within 5 min of contact with elicitors (209/319, 65.5%). Associated characteristics included positive IgE to at least one panallergen (profilin, PR-10, or nsLTP) (p = 0.007), maternal PFAS (OR: 3.716, p = 0.026), and asthma (OR: 1.752, p = 0.073). Between centers, heterogeneity in prevalence (Marseille: 7.5% vs. Rome: 41.4%, p < 0.001) and of clinical characteristics was apparent. Cypress played a limited role, with only 1/22 SPT mono-sensitized patients reporting a food reaction (p < 0.073). CONCLUSIONS: PFAS is a frequent comorbidity in Southern European SAR patients. Significant heterogeneity of clinical characteristics in PFAS patients among the centers was observed and may be related to the different pollen sensitization patterns in each geographic area. IgE to panallergen(s), maternal PFAS, and asthma could be PFAS-associated characteristics.

[The prevalence of oral allergy syndrome: regarding a new classification]. / Prevalencia del síndrome de alergia oral: a propósito de una nueva clasificación.

BACKGROUND: Recently, the oral allergy syndrome (OAS) has been classified according to the foods that induce it: phenotype I, when it is caused only by plant-derived foods; phenotype II, when it is caused by foods of both animal and plant origin. OBJECTIVE: To determine the prevalence of OAS in late teenagers according to the new classification. METHODS: A cross-sectional study in which data from 1,992 teenagers, aged 15-18 year-old, was analyzed; the information was obtained through a structured questionnaire, where questions were asked about oral symptoms according to the type of food that had been ingested. RESULTS: The overall prevalence of OAS was of 1.7% (95% CI = 1.2-2.4); for phenotype I, it was of 0.85% and, for phenotype II, it was of 0.85%. According to the phenotype, there was no difference by sex and personal history of atopic disease; instead, the onset time of the symptoms did show an association with the phenotype (p = 0.048). The frequency of skin and mucosal symptoms and respiratory ailments differed between the groups. Regarding gastrointestinal symptoms, diarrhea was markedly more frequent in phenotype II (p = 0.044). CONCLUSION: Two phenotypes with OAS were clearly identified: the first one was associated exclusively to foods of plant origin, and the other was related to foods of both plant and animal origin.

Antecedentes: Recientemente, el síndrome de alergia oral (SAO) ha sido clasificado de acuerdo con los alimentos que lo inducen: fenotipo I, relacionado con alimentos derivados de plantas; fenotipo II, provocado por alimentos de origen vegetal y animal. Objetivo: Determinar la prevalencia del síndrome de alergia oral en adolescentes tardíos según la nueva clasificación. Métodos: Estudio transversal en el que se analizaron los datos de 1992 adolescentes de 15 a 18 años; la información se obtuvo a través de un cuestionario estructurado, en el que se interrogó acerca de síntomas orales según el tipo de alimento consumido. Resultados: La prevalencia global de síndrome de alergia oral fue de 1.7 % (IC 95 % = 1.2-2.4): fenotipo I, 0.85 % y fenotipo II, 0.85 %. Según el fenotipo no hubo diferencia por sexo e historia personal de enfermedad atópica; el tiempo de inicio de los síntomas sí mostró asociación (p = 0.048). La frecuencia de los síntomas respiratorios, en piel y mucosas no difirieron entre los grupos; respecto a los síntomas gastrointestinales, la diarrea fue notoriamente más frecuente en el fenotipo II (p = 0.044). Conclusión: Se identificaron claramente los dos fenotipos del síndrome de alergia oral: uno asociado con alimentos de origen vegetal y otro a alimentos tanto de origen vegetal como animal.

Epidemiological study of oral allergy syndrome in birch pollen dispersal-free regions.

BACKGROUND: Oral allergy syndrome (OAS) is an immediate allergy caused by a cross-reaction of highly homologous common antigens (pan-allergens) contained in fruits/vegetables and pollen. METHODS: A questionnaire was provided to 6824 outpatient visitors and serum levels of specific IgEs against crude antigens and pan-allergen components were measured to study the relationship between the prevalence of OAS and pollinosis in the Fukui Prefecture where there is almost no dispersal of birch pollen. RESULTS: The prevalence of OAS was 10.8%. The rate of pollinosis complication in the OAS group was 67.4%, and OAS was observed in 16.8% of pollinosis patients. Causative foods in order of frequency were melon, pineapple, kiwi fruit, peach, and apple. A significantly higher number of patients from the OAS group were positive for birch, alder, and timothy grass-specific IgE. The rate of positivity for anti-component IgE corresponding to pollen in OAS group was also significantly higher. Of 34 patients with OAS caused by eating apples, 28 (82.4%) were positive for Mal d1-specific IgE. Of the 52 patients with peach-induced OAS, 41 (78.8%) were positive for Pur p1-specific IgE. The concordance rates between crude antigen-specific IgE and anti-PR-10 component-specific IgE were 87.1% and 93.3% for apple and peach respectively. CONCLUSIONS: In regions where birch pollen is not dispersed, OAS patients have a significant association with the onset of Bet v1-associated allergy. Anti-PR-10 component IgE was useful in diagnosing OAS, and crude antigen-specific IgE was also associated with apple and peach allergies.

Frequency and clinical features of pollen-food syndrome in children.

BACKGROUND: Pollen-food syndrome (PFS) is an allergic reaction to fresh fruits, vegetables and/or nuts that can occur in patients who are allergic to pollen. The prevalence of PFS in children is not clearly known. OBJECTIVE: The objective of this study was to determine the frequency and clinical features of PFS in pediatric patients with pollen-induced allergic rhinitis (AR). METHOD: This study was conducted in the pediatric allergy outpatient clinic of our hospital. Pollen-induced seasonal AR patients who were evaluated for any symptoms appearing after consuming any fresh fruits and vegetables. RESULTS: Six hundred and seventy-two pollen-sensitized patients were included in this study. The symptoms related to PFS were reported in 22 (3.3%) patients. The median age of the patients was 12.3 years and 59% (n=13) were female. Peach was the most common culprit (22%). There were isolated oropharyngeal symptoms in 20 (91%) patients and anaphylaxis in two (9%) patients with the suspected food. The multiple logistic regression analysis revealed that female gender, history of atopic dermatitis and allergic diseases in the family were the potential risk factors for PFS [Odds ratio 95%CI: 3.367 (1.344-8.435), 5.120 (1.935-13.550), 3.046 (1.239-7.492), respectively]. CONCLUSION: PFS can be seen in children who are followed up for pollen-induced AR. The symptoms of PFS are usually mild and transient. However, comprehensive evaluation of patients is important since serious systemic reactions such as anaphylaxis can also be observed.

[LONG-TERM RESULTS OF AIRBORNE POLLEN SURVEYS IN THE JAPANESE ARCHIPELAGO FROM THE PERSPECTIVE OF POLLEN ANTIGEN].

BACKGROUND: In 1986, the Ministry of Health and Welfare started an airborne pollen survey as part of measures against JC pollinosis. We reported the important tree pollen antigens in 2016. We have now estimated the longitudinal investigated results for successful prevention and treatment for allergic symptoms related to grass and weed pollen in Japan. METHOD: Since July 1986 we have monitored airborne pollen, year- round, using a gravitational pollen sampler (Durham's sampler), at more than 20 locations across Japan. Specimens were mailed to our facility, where they were stained with Calberla solution, counted under an optical microscope, and converted to the number of pollen per square centimeter. For convenience the number of collected pollen were compiled every six months, with the January to June samples classified as spring pollen and the July to December as autumn pollen even same family. RESULT: Total pollen counts at each location were extremely small compared to tree-pollen, averaging 73~650 pollen grains per year. The Sagamihara location had the greatest count. Unlike cedar and cypress there were no significant annual fluctuations, but grass and Ambrosia pollen counts are increasing in some regions. Spring grass pollen gave the largest count, at 30% of the total collected. CONCLUSION: This indicated we need to examine the rinoconjuctivitis and oral allergy syndrome related to herbaceous pollen carefully.The importance of airborne pollen surveys for the treatment of the patients with pollen allergies was suggested.

Pollen-Food Allergy Syndrome: A not so Rare Disease in Childhood.

Seasonal allergic rhinoconjunctivitis (SAR) affects millions of people worldwide, particularly in childhood and adolescence. Pollen food allergy syndrome (PFAS) is a common adverse reaction occurring few minutes after the consumption of vegetable foods in patients with pollen-induced SAR. PFAS has rarely been investigated in the pediatric population, as it has been mainly examined as an adult disease. Recent studies suggested that PFAS might be more frequent in childhood than previously recognized. The present review aims to give an overview of the epidemiology, pathophysiology, diagnosis, management and prognosis of PFAS in children with SAR-induced by pollens.

Subcutaneous Immunotherapy in Patients with Fagales Pollen-Induced Oral Allergy Syndrome.

Oral allergy syndrome (OAS) is the most common food allergy-related condition in adults. This study aimed to investigate whether subcutaneous immunotherapy (SCIT) with Fagales pollen-containing extracts can improve the clinical symptoms of OAS in Korea. In total, 56 OAS patients were included: 19 subjects treated with SCIT, which included Fagales pollen extracts, and 37 not treated with immunotherapy (IT). We reviewed the patients' medical records and administered a telephone questionnaire at one point to assess baseline OAS features and changes in the patients' OAS and allergic rhinoconjunctivitis (ARC) symptoms after treatment. Only 12 patients who received SCIT and 15 patients that did not receive SCIT could report on changes in OAS symptoms after treatment because the other patients practiced strict avoidance of their culprit fruits and vegetables, and they could not respond to the status of OAS. SCIT reduced the severity of OAS (p=0.005). Nine of the 12 patients (75%) that received SCIT reported a more than 50% reduction in OAS symptoms. In contrast, only three of the 15 patients (20%) that did not receive IT reported more than a 50% reduction in OAS symptoms. SCIT also reduced the severity of ARC symptoms (p<0.001). The results indicate that SCIT with Fagales pollen-containing extracts is associated with improved OAS symptoms in Korea.

Clinical Characteristics of Oral Allergy Syndrome in Children with Atopic Dermatitis and Birch Sensitization: a Single Center Study.

BACKGROUND: Oral allergy syndrome (OAS) is an immunoglobulin E (IgE)-mediated hypersensitivity that occurs frequently in older children with pollen sensitization. This study focused on the clinical characteristics of OAS in children with atopic dermatitis (AD) and birch sensitization. METHOD: s: A total of 186 patients aged 2-18 years with AD and birch sensitization were enrolled in this study between January 2016 and March 2017. Their levels of serum total IgE and birch- and ragweed-specific IgE (sIgE) were measured using ImmunoCAP (Thermo Fisher Scientific, Uppsala, Sweden). Information regarding causative foods and symptoms were obtained via interviews. The patients were divided into 3 groups according to their ages (group 1, 2-6 years; group 2, 7-12 years; and group 3, 13-18 years). RESULTS: Eighty-one of the 186 (43.5%) children with AD who were sensitized to birch pollen were diagnosed as having OAS. The prevalence of OAS in group 1 (the children who had AD and birch sensitization aged 2-6 years) was 36.6%. A greater predominance of men was noted in the non-OAS group (77.1%) compared to the OAS group (60.5%). Apples were the most common causative food in group 2 and 3 while kiwis were the most common cause of OAS in group 1. There was a statistically significant correlation between birch-sIgE levels and the prevalence of OAS (P = 0.000). The cut-off value was 6.77 kUA/L with 55.6% sensitivity and 79.0% specificity (area under the curve 0.653). CONCLUSION: In our study, the prevalence of OAS in children with AD and birch sensitization was 43.5%. Even in the preschool age group, the prevalence of OAS was considerable. Patients with high levels of birch-sIgE were more likely to have OAS. Clinicians should therefore be vigilant about OAS in patients with a high degree of sensitization to birch pollen and even young children if they have birch sensitization.

Subcutaneous Immunotherapy in Patients with Fagales Pollen-Induced Oral Allergy Syndrome

Oral allergy syndrome (OAS) is the most common food allergy-related condition in adults. This study aimed to investigate whether subcutaneous immunotherapy (SCIT) with Fagales pollen-containing extracts can improve the clinical symptoms of OAS in Korea. In total, 56 OAS patients were included: 19 subjects treated with SCIT, which included Fagales pollen extracts, and 37 not treated with immunotherapy (IT). We reviewed the patients' medical records and administered a telephone questionnaire at one point to assess baseline OAS features and changes in the patients' OAS and allergic rhinoconjunctivitis (ARC) symptoms after treatment. Only 12 patients who received SCIT and 15 patients that did not receive SCIT could report on changes in OAS symptoms after treatment because the other patients practiced strict avoidance of their culprit fruits and vegetables, and they could not respond to the status of OAS. SCIT reduced the severity of OAS (p=0.005). Nine of the 12 patients (75%) that received SCIT reported a more than 50% reduction in OAS symptoms. In contrast, only three of the 15 patients (20%) that did not receive IT reported more than a 50% reduction in OAS symptoms. SCIT also reduced the severity of ARC symptoms (p < 0.001). The results indicate that SCIT with Fagales pollen-containing extracts is associated with improved OAS symptoms in Korea.

Clinical Characteristics of Oral Allergy Syndrome in Children with Atopic Dermatitis and Birch Sensitization: a Single Center Study

BACKGROUND: Oral allergy syndrome (OAS) is an immunoglobulin E (IgE)-mediated hypersensitivity that occurs frequently in older children with pollen sensitization. This study focused on the clinical characteristics of OAS in children with atopic dermatitis (AD) and birch sensitization. METHOD: s: A total of 186 patients aged 2–18 years with AD and birch sensitization were enrolled in this study between January 2016 and March 2017. Their levels of serum total IgE and birch- and ragweed-specific IgE (sIgE) were measured using ImmunoCAP (Thermo Fisher Scientific, Uppsala, Sweden). Information regarding causative foods and symptoms were obtained via interviews. The patients were divided into 3 groups according to their ages (group 1, 2–6 years; group 2, 7–12 years; and group 3, 13–18 years). RESULTS: Eighty-one of the 186 (43.5%) children with AD who were sensitized to birch pollen were diagnosed as having OAS. The prevalence of OAS in group 1 (the children who had AD and birch sensitization aged 2–6 years) was 36.6%. A greater predominance of men was noted in the non-OAS group (77.1%) compared to the OAS group (60.5%). Apples were the most common causative food in group 2 and 3 while kiwis were the most common cause of OAS in group 1. There was a statistically significant correlation between birch-sIgE levels and the prevalence of OAS (P = 0.000). The cut-off value was 6.77 kUA/L with 55.6% sensitivity and 79.0% specificity (area under the curve 0.653). CONCLUSION: In our study, the prevalence of OAS in children with AD and birch sensitization was 43.5%. Even in the preschool age group, the prevalence of OAS was considerable. Patients with high levels of birch-sIgE were more likely to have OAS. Clinicians should therefore be vigilant about OAS in patients with a high degree of sensitization to birch pollen and even young children if they have birch sensitization.

Oral allergy syndrome amongst young Mexicans: prevalence and associated factors.

Summary: Background. Oral allergy syndrome (OAS) is the most common food allergy manifestation amongst adults. However, population studies aimed at estimating its prevalence and associated factors are scarce in Mexi-co. Objectives. To establish the prevalence of OAS in a sample of university students and to describe their clinical characteristics and its associated factors. Methods. From a sample group made up of 25,269 university students, the data corresponding to 1,200 students aged 18 to 25 was analyzed with a cross-sectional approach. A structured questionnaire was used to identify OAS, its symptoms and related foods, and the personal history of atopic diseases. The associations between variables were calculated through logistical regression analysis. Results. The prevalence of OAS was 3.4%, with a 95% confidence interval (95% CI) of 2.5 to 4.6. The main oral symptoms reported were lip pruritus, edema and the sensation of pharyngeal oppression. Among the extra-oral complaints were: reddish coloration of the skin, body pruritus, abdominal pain, and abdominal bloating. The foods that were most frequently associated with OAS were fruits (68.5%), vegetables (22.0%) and seafood (19.3%). Through multivariate analyses, allergy to pollen and latex were found to be associated with OAS, OR 3.29; 95%: CI 1.53 to 7.10 and OR 5.53; 95% CI: 1.08 to 28.2, respectively. Conclusions. Notably, the prevalence of OAS varies according to the geographic area. Personal histories of allergy to pollen or latex were the main factors linked to OAS.

Oral Allergy Syndrome in Birch Pollen-Sensitized Patients from a Korean University Hospital.

BACKGROUND: Oral allergy syndrome (OAS) is a type of allergic reaction that mainly occurs on oral contact with raw fruit, vegetables, or nuts. The most common type of OAS is birch pollen-related food allergy. Although OAS is a common food allergy in adults, only few epidemiologic studies have been reported in Korea. Here we investigate the prevalence and triggers of birch pollen-related food allergy. METHODS: We conducted a retrospective chart review of 1,427 patients who underwent a skin prick test for inhalant allergens at the Asthma and Allergy Clinic in Seoul National University Bundang Hospital from January 2011 to December 2016. RESULTS: Of 1,427 patients, 125 (8.7%) were sensitized to birch pollen. Among them, 20.0% developed OAS, which was the most common food allergy (96.2%). The prevalence of OAS was higher in females, and was 18.2% in birch pollen-sensitized allergic rhinoconjunctivitis patients. Further, 72.0% OAS patients had rhinoconjunctivitis, 20.0% had asthma, and 12.0% had chronic urticaria. Apple (68.0%), peach (56.0%), nuts (36.0%), kiwi (20.0%), persimmon (20.0%), plum (16.0%), and cherry (16.0%) were frequent triggers; however, Chinese yam, kudzu vine, bellflower root, codonopsis, and ginseng were also revealed as triggers. Patients (60.0%) showed OAS with ≥ 3 foods at the same time. Only 3 patients showed mono-sensitivity to birch pollen, while others were multi-sensitized to trees, grasses, weed, or house dust mite allergens. CONCLUSION: OAS was the most common food allergy in birch pollen-sensitized patients. This study revealed the unique triggers of OAS in Korea in addition to well-known triggers.

[EVALUATION OF THE EFFECTIVENESS OF SUBCUTANEOUS IMMUNOTHERAPY USING BIRCH POLLEN EXTRACT FOR POLLEN-FOOD ALLERGY SYNDROME].

BACKGROUNDS: Recently, patients with oral allergy syndrome (OAS) to fruits or vegetables caused by pollenfood allergy syndrome (PFAS) have increased nationwide. We examined effectiveness of SCIT using birch pollen extract for PFAS. METHODS: A total of 19 patients (9 male and 10 female) underwent SCIT with birch pollen extract from August 2011 to August 2016. Rush schedule was used for the initial updosing for SCIT in a hospital setting. In maintenance phase, SCIT was administered every 4-8 weeks on an outpatient basis. According to the situation of sensitization, patients underwent SCIT with other extracts at the same time. Oral food challenge (OFC) with fruits and vegetables was performed at baseline and after rush phase. We also investigated about OAS symptoms in maintenance phase. RESULTS: SCIT was remarkably effective in five patients for OAS symptoms just after rush phase, and effective in nine patients. And it was not effective in two patients, and not determined in three patients, but it was confirmed to be effective in four out of these five patients in maintenance phase. There were relapse of OAS symptoms in three patients, then SCIT was remarkably effective or effective in 15 patients (79%) in maintenance phase. No patients dropped off the SCIT protocol. CONCLUSIONS: Generally, PFAS can't be expected to remit naturally. SCIT with birch pollen extract effectively reduces OAS symptoms, and it can be expected as a radical therapy for PFAS.

Etiology and clinical feature of oral allergy syndrome in children

PURPOSE: Oral allergy syndrome (OAS) is a unique allergic reaction to fresh fruits or vegetables, which is caused by cross-reactivity between foods and pollens. This study was conducted to investigate the clinical feature of OAS and relevant pollen allergens as well as the association between them in Korean children. METHODS: This single-center study included 290 children who were sensitized to pollens at Severance Hospital, and the clinical characteristics of children with and without OAS were compared. A multicenter study included 97 children who were diagnosed with OAS at 3 hospitals between January 2008 and June 2014. The details of clinical features were collected by retrospective medical record reviews using a standardized case report form. The relevant pollen allergens were identified by skin prick tests and/or serum specific IgE levels. RESULTS: The most commonly sensitized allergen was Japanese hop in pollen-sensitized children. Children with OAS were most commonly sensitized to birch and oak, and 12.4% of the pollen-sensitized children had OAS in the single center. The number of children who were newly diagnosed with OAS has increased over the past 7 years. The most common causative food of OAS was apple. More than 60% of patients with OAS had oral allergic reactions to multiple foods. CONCLUSION: OAS may be relatively common in pollen-sensitized children. OAS should be considered in children with allergic disease and sensitization to pollens.