Beyond sensitization: real-life thresholds for cat allergy in children

English (OpenAlex)

Background: Cat sensitization is common in patients with allergic diseases and may not always produce clinical symptoms. Objective: This study aimed to assess the correlation between skin prick test (SPT), cat-specific immunoglobulin E (cat sIgE), and symptoms in sensitized children, and to determine optimal thresholds and predictors for clinical cat allergy. Methods: We retrospectively evaluated 1052 cat-sensitized children (2017–2024) who underwent SPT and/or cat sIgE testing. Patients were grouped by presence of cat-related symptoms, and their clinical, laboratory, co-sensitization, and exposure characteristics were compared. Results: Clinical symptoms developed after exposure in 39% of cat-sensitized patients. The optimal cat sIgE cut-off was 1.05 kU/L (sensitivity 71.4% and specificity 93.0%), and 4.5 mm for SPT (sensitivity 64.1% and specificity 75.9%). Multivariate analysis identified cat sIgE positivity as the only independent risk factor for symptom development (odds ratio [OR]: 23.22, 95% confidence interval [ 95% CI]: 11.62–46.39). Environmental exposure characteristics were significant in univariate analysis; in particular, contact at home (OR: 2.35; 95% CI: 1.48–3.71; P < 0.001), family visitation/indoor contact (OR: 2.99; 95% CI: 1.88–4.74; P < 0.001), and sharing a household with a cat (OR: 3.74; 95% CI: 1.78–7.85; P < 0.001) were associated with symptom development. Positivity for the house dust mites Dermatophagoides farinae (OR: 1.59; P < 0.001) and Dermatophagoides pteronyssinus (OR: 1.65; P < 0.001) and grass pollen sensitization (OR: 1.69; P < 0.001) were also significantly associated with symptomatic patients. Conclusions: Cat sIgE positivity independently predicts symptoms, with 1.05 kU/L for sIgE and 4.5 mm for SPT identified as reliable diagnostic cut-offs.