Serum LDH, eosinophils, and IgE in atopic dermatitis severity: a retrospective study

Aims To evaluate serum lactate dehydrogenase (LDH), eosinophils, and total immunoglobulin E (IgE) as accessible adjunctive markers of atopic dermatitis (AD) severity.Materials & methods This retrospective study included 265 AD patients and 97 healthy controls. SCORAD scores and laboratory biomarkers obtained within 48 hours were analyzed using ordinal logistic regression. A binary logistic model was used for ROC analysis of severe AD.Results Severe AD was associated with higher LDH, eosinophil counts, and total IgE than mild-moderate AD. LDH and eosinophils correlated with SCORAD scores (r = 0.61 and r = 0.45, both p < 0.001), while IgE showed a significant non-linear quadratic trend (p < 0.001). Older age, longer disease course, LDH, eosinophils, total IgE, and personal atopy (OR = 2.94) were independently associated with greater severity. The combined biomarker model yielded an AUC of 0.88 for severe AD.Conclusion LDH, eosinophils, and total IgE were independently associated with SCORAD-defined AD severity. Their combined assessment may complement, but not replace, clinical scoring; prospective validation is required.