Background: Childhood allergic rhinitis (AR) is clinically heterogenous. We aimed to identify distinct phenotypes among children with AR using data‐driven techniques and to ascertain their association with patterns of symptoms, allergic sensitization, and comorbidities.Methods: We recruited 510 children with physician‐diagnosed AR, of whom 205 (40%) had asthma. Latent class analysis (LCA) was performed to identify latent structure within the data set using 17 variables (allergic conjunctivitis, eczema, asthma, family history of asthma, family history of allergic rhinitis, skin sensitization to 8 common allergens, tonsillectomy, adenoidectomy).Results: A four‐class solution was selected as the optimal model based on statistical fit. We labeled latent classes as: (1) AR with grass mono‐sensitization and conjunctivitis (n = 361, 70.8%); (2) AR with house dust mite sensitization and asthma (n = 75, 14.7%); (3) AR with pet and grass polysensitization and conjunctivitis (n = 35, 6.9%); and (4) AR among children with tonsils and adenoids removed (n = 39, 7.6%). Perennial AR was significantly more common among children in Class 2 (OR 5.83, 95% CI 3.42–9.94, p < .001) and Class 3 (OR 2.88, 95% CI 1.36–6.13, p = .006). Mild and intermittent AR symptoms were significantly more common in children in Class 2 compared to those in Class 1. AR was more severe in Class 1 compared to other 3 classes, indicating that upper respiratory symptoms are more severe among children with isolated seasonal rhinitis, than in those with rhinitis and coexisting asthma.Conclusion: We have identified 4 phenotypes in school‐age children with AR, which were associated with different patterns of clinical symptoms and comorbidities.

Background: The aim of this study was to investigate the association of serum periostin levels with clinical features in children with asthma.Methods: Children with physician‐diagnosed asthma who attended regularly to an outpatient pediatric allergy and asthma center were enrolled in the study along with control subjects. Asthma severity and control status of the patients were evaluated according to the recent GINA guidelines.Results: A total of 158 children (125 with asthma and 33 age‐ and sex‐matched control subjects) with a median age of 10.2 years (range 5.9‐17.0) were enrolled. Asthma severity was mild in 41 (32.8%), moderate in 63 (50.4%), and severe in 21 (16.8%) children. Children with asthma had significantly higher periostin levels than controls (53.1 ± 13.1 vs 43.0 ± 11.2 ng/mL, P < .001). The mean serum periostin levels in children with severe asthma (63.8 ± 10.8) were significantly higher than in children with moderate asthma (53.3 ± 12.7) and mild asthma (47.4 ± 11.1) (P < .001). Results of multivariable logistic regression analysis demonstrated an association between serum periostin levels and asthma severity in children (OR, 1.10; 95% CI, 1.04‐1.15, P < .001). When analyzed for the best cut‐off value with the highest combined sensitivity and specificity, a cut‐off value of 52 ng/mL for serum periostin level was obtained with sensitivity, specificity, PPV, and NPV of 100%, 50%, 29%, and 100%, respectively.Conclusion: Although serum periostin levels are higher in children with asthma, its diagnostic role in identifying children with severe asthma is limited.

We report a 15-year-old boy who developed aseptic meningitis 10 days after administration of the second dose of the COVID-19 vaccine BNT162b2. Although accompanying aphthous mouth ulcers resembling herpetic stomatitis initially led us to suspect an underlying viral infection, broad virological and microbiological screening did not identify any causative pathogen. Gonarthritis and skin lesions, which both developed within three days after admission, extended the clinical presentation eventually resembling an acute Behçet’s disease episode. This is the first description of a juvenile patient with aseptic and pathogen-negative meningitis occurring in close temporal association with vaccination against COVID-19, along with a few previously reported adult patients with isolated meningitis and a further case with meningitis and an accompanying Behçet’s disease-like multisystem inflammation episode as seen in our patient. With billions of individuals being vaccinated worldwide so far and only a few cases of aseptic pathogen-negative meningitis reported in close temporal relation, causality is unclear. However, aseptic meningitis should be kept in mind in the differential diagnosis of patients with persistent or delayed onset of headache and fever following COVID-19 vaccination.

Background Many children encounter unusual or “exaggerated” reactions such as large local, atypical or systemic reactions after mosquito bites. Objective The aim of this study was to document the clinical features of children with mosquito allergy and investigate the possible associations between demographic features and type of reactions in this population. Methods Children with large local or unusual reactions after mosquito bites who attended to our outpatient pediatric allergy department were enrolled in the study along with control subjects. Results A total of 180 children (94 with mosquito allergy and 86 age and sex-matched control subjects) with a median age of 6.8 years (IQR 5.5–9.3) were enrolled. Atopy (35.1% vs. 11.6%, p < 0.001) and grass pollen sensitization (28.7% vs. 8.1%, p < 0.001) were significantly more frequent in children with mosquito allergy. Skin prick test with mosquito allergen was positive in only 6 children (6,4%). Grass pollen sensitization was most common in children (28.7%) followed by sensitization to house dust mite (9.6%). 30 children (31.9%) had an accompanying atopic disease such as allergic rhinitis, asthma or atopic dermatitis. Bullae were significantly more frequent in children with asthma (41.7% vs.15.9, p = 0.034). The median duration of symptoms after onset were significantly longer in patients with ecchymosis, with immediate wheals and in children whose symptoms start in 20 min to 4 hours after mosquito bites. Conclusion There is an association between unusual, large local or exaggerated reactions after mosquito bites and allergic diseases in children. The severity of reactions increases with age and particularly in children with atopic background.