Hypogammaglobulinemia in Children with Atopic Dermatitis

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease among children. Our study aimed to evaluate the prevalence of hypogammaglobulinemia among pediatric patients with AD and to characterize the clinical and laboratory findings of patients diagnosed with AD and hypogammaglobulinemia.

The electronic files of 1850 patients aged 0-18 years diagnosed with AD between 2020 and 2022 in the Pediatric Immunology and Allergy Clinic of Bursa Medical Faculty City Hospital were retrospectively analyzed. During this period, all patients newly diagnosed with atopic dermatitis at our clinic were systematically screened for their serum immunoglobulin (Ig) levels (IgG, IgA, and IgM) at the time of initial presentation. We included 200 AD patients with hypogammaglobulinemia. Disease severity was classified using the Scoring Atopic Dermatitis (SCORAD) index. Multivariate logistic and linear regression analyses were performed to identify independent determinants of disease severity, considering age, sex, eosinophil counts, total IgE, food allergies, and baseline immunoglobulin levels.

The prevalence of hypogammaglobulinemia among the 1850 screened children with AD was 10.8% (200/1850). Of the 200 patients included in this study, 128 (64%) were male, and 72 (36%) were female. The median age at first clinic presentation was 8 months (interquartile range (IQR) 25-75%: 5-16). According to the Scoring Atopic Dermatitis (SCORAD) index, AD severity was mild in 150 (75%) patients and moderate-to-severe in 50 (25%). Food allergy sensitization was present in 72 (36%) patients. Patients with moderate-to-severe AD had significantly lower IgG (300 vs. 374 mg/dL; p < 0.001; r = -0.346), IgA (10 vs. 14 mg/dL; p = 0.004), and IgM (38 vs. 51 mg/dL; p = 0.001) levels when compared with those with mild disease. Multivariate logistic regression confirmed that lower IgG was the only immunoglobulin independently associated with moderate-to-severe AD (OR = 1.97 per 100 mg/dL decrease; 95% CI: 1.15-3.39; p = 0.013), while food allergy was the strongest independent predictor of the SCORAD index (β = +11.97; p < 0.001). None of the patients received intravenous immunoglobulin (IVIG) treatment. Of the 142 patients who underwent serial serum immunoglobulin measurements, 56 (39%) achieved age-appropriate normal IgG levels, while hypogammaglobulinemia persisted in 86 (61%).

We found a higher frequency of hypogammaglobulinemia in patients with AD in our study, as compared with previously reported rates of THI in children from the general pediatric population. Although our study showed an increase in IgG levels during the follow-up period in many patients, it emphasizes the need for long-term immunological monitoring, especially in patients with moderate-to-severe AD.