Low serum immunoglobulin levels in pediatric atopic dermatitis: association with disease severity and exploratory scores.

UNLABELLED: Atopic dermatitis (AD) is a common chronic inflammatory skin disease in childhood. Although low serum immunoglobulin (Ig) levels have been reported in children with AD, their clinical significance and association with disease severity remain insufficiently defined. We aimed to evaluate the association between serum Ig levels and AD severity and to characterize the clinical and immunologic course of affected children. In this retrospective-prospective cohort study, 241 children younger than 5 years with AD were evaluated between 2021 and 2023. Patients were classified into an AD group (n = 139) and an AD-low Ig group (n = 102) according to age-adjusted baseline serum Ig levels. Disease severity was assessed using SCORAD and 2 exploratory scoring tools: the Involvement Area Score (IAS) and the Skin Findings Score (SFS). Low serum Ig levels, most commonly isolated IgG deficiency (65.7%), were identified in 42% of the cohort. Lower IgA, IgG, and IgM levels were significantly associated with greater disease severity (p < 0.05), and SCORAD showed a strong negative correlation with IgG levels (ρ =  - 0.535, p < 0.001). During follow-up, 52.7% of patients in the AD-low Ig group had persistent Ig abnormalities, which were associated with more severe AD. IAS and SFS correlated strongly with SCORAD and were significantly higher in the AD-low Ig group (p < 0.05).

CONCLUSION

Low baseline serum Ig levels may predict a more severe clinical course and that persistent severe AD may be accompanied by ongoing Ig abnormalities. IAS and SFS provide practical and objective tools for assessing disease extent and morphology in routine practice.

WHAT IS KNOWN: • Atopic dermatitis (AD) is the most common chronic inflammatory skin disease in childhood. • Low serum immunoglobulin levels may occur in some children with AD, but their associations with disease severity and longitudinal clinical course remain unclear.

WHAT IS NEW: • Novel exploratory scoring tools show strong correlation with SCORAD and may serve as practical, objective measures for severity assessment in routine clinical monitoring. • The association of low serum Ig levels with greater disease severity and persistence in pediatric AD supports a risk-based immunologic assessment, particularly in children with severe, early-onset disease, recurrent infections, or extensive skin involvement.