Objective: To analyze the significance of detecting leukocyte derived markers, 25 hydroxyvitamin D, and immunoglobulin in patients with allergic purpura. Methods: A total of 89 patients with allergic purpura admitted to our hospital from 2021 to 2024 were selected and divided into case groups, and another 89 healthy volunteers admitted for physical examination in our hospital during the same period were selected as the control group. The leukocyte-derived index [lymphocyte to monocyte ratio (LMR), platelet to lymphocyte ratio (PLR), neutrophil to lymphocyte ratio (NLR)], 25 hydroxyvitamin D [25- (OH) D] and immunoglobulin [immunoglobulin (Ig) G, IgA, IgM, complement C3, complement C4], the working characteristics (ROC) curve, and the analysis of leukocyte-derived indicators, 25 hydroxyvitamin D, the diagnostic value of immunoglobulin in allergic purpura. Subsequently, the patients were divided into mild (31), moderate (37), and severe (21) according to their severity, their leukocyte-derived indicators, 25- (