Polyethylene glycols (PEGs) and their derivatives are non-ionic polymers of ethylene oxide commercially available with numerous synonyms, such as macrogol, oxyethylene polymer, and laureth-9. Although these polymers are usually safe, mild to life-threatening immediate-type hypersensitivity reactions have been reported. Nevertheless, awareness about their allergic potential is minimal due to the non-standardization of their nomenclature. We present the case of a 29-years-old woman who developed several local and systemic type I hypersensitivity reactions including a severe anaphylactic reaction to different pharmacologic and cosmetic products whose excipients included PEG. Prick tests and basophil activation tests were performed to several pharmacological and cosmetic products, but only those containing PEGs and their derivatives were positive. The patient was diagnosed with immediate hypersensitivity IgE-mediated to PEGs and its derivatives. Standardization of the terminology used to describe the presence of PEGs in products would help patients to identify them clearly and unequivocally and thus avoid the development of hypersensitivity reactions. It is also recommended studying PEG allergy in reactions to products containing PEGs, once allergy to the active ingredients has been excluded and in reactions to multiple unrelated drugs. Clinical study protocol number PI2018/29 (registered on 24 September 2018)

Eosinophilic esophagitis (EoE) is a complex pathology. Attempts have been made in order to relate EoE with the intake of certain food. The problem is to establish which foods are really involved in the pathophysiology of this condition and to objectify a reliable inflammation biomarker for the follow-up of patients undergoing pharmacological treatment and/or diets. Our aim is to assess the food sensitization profile of patients with objective diagnosis of EoE and objectify the utility of ECP as an inflammation biomarker for the follow-up of patients with EoE treated with specific diets, based on the hypothesis that we will observe a decrease and clinical improvement after maintenance of these diets. A total of 19 subjects were included between 1 January 2012 and 30 June 2015. Diets based on allergy testing were established. Prior to the initiation of the diets, baseline ECP was determined. Appointments were arranged for the patients between 4 and 6 months later to assess the clinical response to the specific diets and to request a second blood sample for blood counts and serum ECP levels to compare with the previous baseline. 19 patients diagnosed with EoE (12 males and 7 females) between January 2012 and June 2015, aged between 17 and 68 (33.52; SD 13.67 years), were included consecutively, 15 of whom showed optimum response to specific diets based on allergy testing. A statistically significant difference ECP decrease was observed in our patients. Until now most of the studies previously published in reference to the use of ECP as a biomarker for monitoring patients on treatment with diets show consistent but insignificant decreases in ECP levels. However, ECP seems to be a good marker of inflammation if the determinations are performed avoiding confounding factors. The serial determination of ECP is useful when monitoring patients with EoE treated with specific diets.

Background: One of the main barriers to vaccination against SARS-CoV-2 is the fear of developing hypersensitivity reactions to any of its components. Although these reactions are very rare, it is necessary to establish an effective protocol to detect patients at risk of developing them. The aim of this study was to evaluate hypersensitivity reactions in vaccinated patients in order to allow or not to complete the vaccination protocol. Methods: Descriptive and cross-sectional study in which patients with suspected hypersensitivity to SARS-CoV-2 vaccines were evaluated. All patients underwent skin prick test (SPT) and/or intradermal test (IDT) with the vaccines and their excipients. In patients with positive IDT with the vaccine, a histopathological and immunohistochemical study was performed by skin biopsy. A basophil activation test (BAT) and a lymphoblastic transformation test (LTT) were also performed. Results: Sixteen patients with suspected hypersensitivity to SARS-CoV-2 vaccine (12 received Comirnaty^®, 3 received Vaxzevria^®, and 1 received Spikevax^®) were evaluated. Half had immediate hypersensitivity reactions and half had delayed reactions. All SPTs to excipients and vaccines were negative. IDTs with all excipients were negative. IDTs with vaccines were positive in 11 patients and negative in 5. The histological and immunohistochemical study of the two selected patients with positive IDT with vaccine showed T-lymphocyte involvement. BAT and LTT were negative in both cases. The vaccination protocol could be completed in 7 of 16 patients (44%) studied. The remaining 9 patients did not receive the second dose: 5 because vaccination was not required and 4 because they refused to be vaccinated. Conclusions: Thanks to the allergological and immunohistochemical study, the vaccination protocol could be completed in about half of the patients who presented suspected hypersensitivity reactions to SARS-CoV-2 vaccines. IDTs with vaccines could be a valuable method for assessing the immunogenicity of the vaccines.

Background: The pathophysiological mechanism of eosinophilic esophagitis (EoE) is complex and is still being investigated. We believe that there is a group of patients with eosinophilic esophagitis which could be differentiated as having an allergic phenotype who exhibit a sensitization profile (aeroallergens, panallergens, foods and specific IgG4 levels) with significant differences compared to patients with conventional allergic disease without associated eosinophilic esophagitis and healthy controls. Method: We measured the prevalence of sensitization to aeroallergens, foods and panallergens by means of molecular diagnostic techniques (ImmunoCAP^TM ISAC) and determined the levels of specific IgG4 against foods and eosinophilic-derived neurotoxin (EDN) (ImmunoCAP technology) in patients with EoE of an allergic phenotype to study whether there are statistically significant differences with respect to the control groups (patients with different allergic pathologies without EoE and healthy patients without documented allergies). The total number of patients under study was 118, distributed among the different study groups. The case group (Allergic phenotype EoE patients) had 48 subjects. The food and respiratory allergy control groups had 30 subjects each. Finally, we included 10 in the healthy control group. Results: We were able to identify statistically significant differences when comparing levels of food-specific IgG4. Milk, egg, wheat, nuts, soy, cod, and Pru p3/LTP stood out. We did not observe significant differences in relation to sensitization to aeroallergens, foods, or panallergens. We also did not observe differences in EDN levels. Conclusions: We present a study in which statistically significant differences in IgG4 levels were observed in response to different types of food, comparing patients with eosinophilic esophagitis of allergic phenotype (case group) against subjects with allergic pathology without EoE and healthy subjects (control groups). Determining whether the detected foods are clinically relevant or not in these patients would be fundamental to establishing their usefulness as a treatment alternative in our patients.

Background: Eosinophilic esophagitis (EoE) pathophysiological mechanism is complex and it s still being investigated. We believe there is a group of patients with eosinophilic esophagitis which we could differentiate as having an allergic phenotype, who exhibit a sensitization profile (aeroallergens, panallergens, foods and specific IgG4 levels) with significant differences when compared to patients with conventional allergic disease without associated eosinophilic esophagitis and healthy controls. Method: We have measured the prevalence of sensitization to aeroallergens, foods and panallergens by means of molecular diagnostic techniques (ImmunoCAPTM ISAC) and determined the levels of specific IgG4 against foods and eosinophilic derived neurotoxin (EDN) (ImmunoCAP technology) in patients with EoE of allergic phenotype to study if there are statistically significant differences with respect to the control groups (patients with different allergic pathologies without EoE and healthy patients without documented allergies). The total number of patients under study was 118, distributed among the different study groups. The case group (Allergic phenotype EoE patients) has 48 subjects. The food and respiratory allergy control groups, 30 subjects each. Finally, we included 10 in the healthy control group. Results: We were able to identify statistically significant differences when comparing levels of food-specific IgG4. Milk, egg, wheat, nuts, soy, cod, and LTP stood out. We did not observe significant differences in relation to sensitization to aeroallergens, foods, or panallergens. We also did not observe differences in EDN levels. Conclusion: We present a study in which statistically significant differences in IgG4 levels were observed in response to different types of food, comparing patients with eosinophilic esophagitis of allergic phenotype (case group) against subjects with allergic pathology without EoE and healthy subjects (control groups). Determining whether the detected foods are clinically relevant or not in these patients would be fundamental to establishing their usefulness as a treatment alternative in our patients.