The reported incidence of immediate hypersensitivity reactions (IHR) including anaphylaxis after COVID-19 vaccination is 10-fold higher than for other vaccines. Several patient groups are theorized to be at particular risk. Since specific vaccination guidelines for these patients are based on expert opinion, we performed a retrospective monocentric analysis of the tolerability of adenoviral vector and mRNA-based COVID-19 vaccines in a cohort of patients allegedly at high risk of IHR. Reactions were assessed immediately on-site by allergists during a monitored vaccination protocol and after 3–7 days through telephone interviews. The cohort included 196 patients (aged 12–84 years) with primary mast cell disease (pMCD, 50.5%), idiopathic anaphylaxis (IA, 19.9%), hereditary angioedema (HAE, 5.1%) or miscellaneous indications (24.5%). Twenty-five immediate reactions were observed in 221 vaccine doses (11.3%). Most occurred in IA or miscellaneous patients. None fulfilled anaphylaxis criteria and most were mild and self-limiting. Reaction occurrence was significantly associated with female sex. In total, 13.5% of pMCD patients reported mast cell activation-like symptoms within 72 h post-vaccination. All pediatric pMCD patients (n = 9, 12–18 years) tolerated both mRNA-based vaccine doses. In summary, adenoviral vector and mRNA-based COVID-19 vaccines were safe and well-tolerated in patients with pMCD, HAE, and IA. No anaphylaxis was observed. The mild and subjective nature of most reactions suggests a nocebo effect associated with vaccination in a medicalized setting. Patients with pMCD could experience mild flare-ups of mast cell activation-like symptoms, supporting antihistamine premedication.

Background: Eosinophilic esophagitis is a chronic immune-mediated disease with increasing prevalence. In pediatric populations, it often coexists with IgE-mediated food sensitization. This dual diagnosis presents unique therapeutic challenges, including on the one hand both temporary and lifelong dietary restrictions, and on the other hand, therapeutic interventions with a potential impact on quality of life (QoL). Objectives: This study prospectively evaluated the prevalence of IgE-mediated food sensitization and allergy in children with EoE attending a tertiary center in Flanders, Belgium. Additionally, it prospectively documented dietary habits and restrictions in these children, with or without concomitant IgE-mediated food allergies, and assessed the impact of dietary management on quality of life compared to pharmacological treatment. Methods: We consecutively followed 30 children with biopsy-confirmed pediatric EoE (PedEoE) attending a tertiary referral center for at least 12 months. Patient demographics, allergy testing, dietary history, and treatment modalities were recorded. Symptom score and PedEoE QoL were assessed using validated Pediatric Eosinophilic Esophagitis Symptom Score (PEESS 2.0) and Pediatric Quality of Life Inventory (PedsQL 3.0) questionnaires. Statistical analysis was performed using the Mann–Whitney U test and Kruskal–Wallis test with Dunn’s test as a post hoc test. Results: Among 30 children with EoE (60% male, median age 8 years), 60 PedEoE QoL (PedsQL) and 39 symptom (PEESS) questionnaires were collected at one or more time points over a median follow-up of 14.5 months. IgE sensitization to common dietary triggers was observed in multiple patients, with varying clinical reactivity. Symptom scores tended to be higher in children without histological remission, though differences were not statistically significant (median PEESS 23.75 vs. 17.50, p = 0.1934). Grouped by degree of dietary restriction, QoL scores showed significant differences (child p = 0.0102; parent p = 0.0203), with children in the 1–2 food elimination group reporting better QoL compared to the 0 food elimination and >6 food elimination groups. No clear statistically significant differences were observed between the 1–2 food elimination group and the 3–4 or 5–6 food elimination groups. Conclusions: IgE sensitization is prevalent among pediatric EoE patients and has significant clinical implications for disease management. Treatment choice can influence not only disease control but also the QoL of both patients and their families.

Background. A novel coronavirus identified in 2019 leads to a pandemic of severe acute respiratory distress syndrome with important morbidity and mortality. Initially, children seemed minimally affected, but there were reports of cases similar to (atypical) Kawasaki disease or toxic shock syndrome, and evidence emerges about a complication named paediatric inflammatory multisystem syndrome temporarily associated with SARS-CoV-2 (PIMS-TS) or multisystem inflammatory syndrome in children (MIS-C). Case Presentations. Two cases were compared and discussed demonstrating varying presentations, management, and evolution of MIS-C. These cases are presented to increase awareness and familiarity among paediatricians and emergency physicians with the different clinical manifestations of this syndrome. Discussion. MIS-C may occur with possible diverse clinical presentations. Early recognition and treatment are paramount for a beneficial outcome.

Background: Eosinophilic esophagitis is a chronic immune-mediated disease with increasing prevalence. In pediatric populations, it often coexists with IgE-mediated food sensitization. This dual diagnosis presents unique therapeutic challenges, including on the one hand both temporary and lifelong dietary restrictions and on the other hand therapeutic interventions with a potential impact on quality of life (QoL). Objectives: This study prospectively evaluated the prevalence of IgE-mediated food sensitization and allergy in children with EoE attending a tertiary center in Flanders, Belgium. Additionally, it prospectively documented dietary habits and restrictions in these children, with or without concomitant IgE-mediated food allergies, and assessed the impact of dietary management on quality of life compared to pharmacological treatment. Methods: We consecutively followed 30 children with biopsy-confirmed pediatric EoE (PedEoE) attending a tertiary referral center, for at least 12 months. Patient demographics, allergy testing, dietary history and treatment modalities were recorded. Symptom score and PedEoE QoL was assessed using validated Pediatric Eosinophilic Esophagitis Symptom Score (PEESS 2.0) and Pediatric Quality of Life Inventory (PedsQL 3.0) questionnaires. Statistical analysis was performed using Mann-Whitney U test and Kruskal-Wallis test with Dunn’s test as a post-hoc test. Results: Among 30 children with EoE (60% male, median age 8 years), 60 PedEoE QoL (PedsQL) and 39 symptom (PEESS) questionnaires were collected at one or more time points over a median follow-up of 14.5 months. IgE sensitization to common dietary triggers was observed in multiple patients, with varying clinical reactivity. Symptom scores tended to be higher in children without histological remission, though differences were not statistically significant (median PEESS 23.75 vs. 17.50, p = 0.1934). Grouped by degree of dietary restriction, QoL scores differed significantly (child p = 0.0102; parent p = 0.0203), with better QoL for children and parents when 1 or 2 food products were excluded from the diet in comparison to more excluded food products or treatment by medication only. Conclusions: IgE sensitization is prevalent among pediatric EoE patients and has significant clinical implications for disease management. Treatment choice can influence not only disease control but also the QoL of both patients and their families.