Background: Skin prick testing (SPT) and serum egg white–specific IgE (sIgE) support oral food challenge (OFC) decisions in suspected egg allergy, but the incremental value of histamine-normalized SPT indices remains uncertain. Methods: In this single-center retrospective study, 105 egg-sensitized children underwent clinically indicated OFC. Commercial egg white SPT, prick-to-prick testing with fresh egg white, histamine controls, and serum egg white–specific IgE were assessed. Discriminatory performance was evaluated by ROC analysis, and independent predictors of OFC positivity were identified using multivariable logistic regression. Results: OFC was positive in 23 of 105 children (21.9%). Egg white SPT wheal diameter, the prick-to-histamine ratio, and serum egg white–specific IgE (sIgE) levels were significantly higher in OFC-positive patients (all p < 0.001). ROC analysis demonstrated moderate-to-good discrimination for both sIgE (AUC = 0.767) and the prick-to-histamine ratio (AUC = 0.786), without clear superiority of normalized indices. In multivariable logistic regression analysis, only absolute egg white SPT wheal diameter (adjusted OR 1.41 per 1 mm increase; 95% CI 1.13–1.77) and serum egg white–specific IgE level (adjusted OR 31.86 per 100 kUA/L increase; 95% CI 1.60–636.15) remained independent predictors of OFC positivity. Conclusions: Absolute egg white SPT wheal diameter and serum sIgE independently predict OFC outcomes in egg-sensitized children. Histamine-normalized indices did not provide added value over wheal size alone. These findings support a probabilistic, context-based use of test results to inform selective OFC planning rather than replace OFC.

Introduction: Immunoglobulin G (IgG) subclass deficiencies are among the most common primary immunodeficiencies in children and are associated with increased susceptibility to infections. This study aimed to investigate the clinical features, associated immunological conditions, and treatment outcomes in affected pediatric patients. Methods: A retrospective analysis was conducted on 43 patients diagnosed with IgG subclass deficiency at the Allergy and Immunology Clinic of Fırat University between January 2019 and July 2024. Clinical records were reviewed for demographic data, immunoglobulin levels, and history of infections. The impact of prophylactic treatments—including intravenous immunoglobulin (IVIG), oral bacterial lysates, and antibiotics—on the frequency of infection was evaluated. Results: Among the 43 patients, 32 (74.4%) were male and 11 (25.6%) were female, with a mean age at diagnosis of 6.77 ± 2.30 years. The most common clinical presentation was recurrent upper respiratory tract infections, reported in 23 patients (53.5%). Isolated IgG3 deficiency was identified in 34 patients (79.1%). During follow-up, normalization of IgG levels was achieved in 39 patients (90.7%), with a mean time to normalization of 2.1 ± 1.19 years. Prophylactic interventions significantly reduced the annual infection rate from 18.12 ± 10.37 to 3.09 ± 2.40 (p < 0.001). Conclusion: IgG subclass deficiencies represent a significant health concern in children because of their association with recurrent infections. Early diagnosis and the implementation of appropriate prophylactic treatment strategies are crucial in reducing infection frequency and improving the quality of life. However, the retrospective nature of the study and the relatively small sample size may have limited the evaluation of clinical outcomes and treatment responses, potentially affecting the generalizability of the results. Despite these limitations, the findings highlight the potential benefits of prophylactic interventions in managing infections among children with IgG subclass deficiencies and emphasize the need for larger, prospective studies to inform evidence-based therapeutic strategies for this population.

Background: To investigate the diagnostic value of the SPT-to-histamine ratio, casein-specific immunoglobulin E (IgE), and cow’s milk-specific IgE in predicting oral food challenge (OFC) positivity in children with suspected cow’s milk allergy. Methods: In this single-center retrospective observational study, 126 children evaluated for suspected cow’s milk allergy who underwent OFC between January 2019 and July 2024 at a tertiary pediatric allergy and immunology center were included. Demographic and clinical characteristics, SPT parameters, and laboratory biomarkers were analyzed. Discriminatory performance was assessed using receiver operating characteristic (ROC) analysis, and independent predictors were identified using multivariable logistic regression. Results: OFC was positive in 66 patients (52.4%). Casein-specific IgE demonstrated strong discriminatory performance (AUC = 0.878), with 80.3% sensitivity and 85.0% specificity at a cutoff value of ≥2.55 kUA/L. The SPT-to-histamine ratio showed moderate discriminatory performance (AUC = 0.758). In multivariable analysis, only casein-specific IgE remained an independent predictor of OFC positivity (adjusted OR = 1.317, p < 0.001). Conclusions: Casein-specific IgE is a strong independent predictor of OFC positivity. Although SPT-derived ratios may provide complementary diagnostic information, their independent predictive contribution appears limited. These findings support the role of component-resolved diagnostics in pre-challenge risk stratification.

Background: This study aimed to investigate the potential utility of hematological parameters and systemic inflammatory indices as predictive biomarkers in pediatric patients with drug hypersensitivity reactions (DHRs).Methods: We performed a retrospective review of medical records of children presenting to the Pediatric Allergy and Immunology Clinic at Fırat University Hospital, Turkey, between January 2019 and July 2025 with suspected DHRs. Demographic characteristics, clinical manifestations, reaction phenotypes, complete blood counts, and total immunoglobulin E (IgE) levels were analyzed. Inflammatory indices, such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), eosinophil-to-lymphocyte ratio (ELR), and systemic immune–inflammation index (SII), were calculated subsequently.Results: Among the 45 children included, drug allergy was confirmed in 14 (31.1%) children. Total IgE levels did not differ significantly between groups (P = 0.712). Monocyte counts were significantly higher in the patient group (P = 0.039), whereas eosinophil counts were elevated in the control group (P = 0.026). Lymphocyte (P = 0.002) and basophil counts (P = 0.002) were significantly lower in the patient cohort. No significant differences were observed in neutrophil or platelet counts. Regarding inflammatory indices, NLR (P = 0.007), PLR (P = 0.006), and SII (P = 0.007) were significantly increased in the patient group, whereas ELR did not differ significantly (P = 0.073).Conclusion: In this small, single-center cohort (n = 45; confirmed DHR, n = 14), higher NLR, PLR, and SII were observed among children with confirmed DHRs. These preliminary findings suggest that readily available hematological indices may aid hypothesis generation and tentative risk stratification; however, they should be interpreted cautiously and require confirmation in larger prospective studies.