Aim To investigate the distribution and histopathological features of cerebral artery stenosis in patients with abnormal serum immunoglobulin E(IgE) and unknown etiology. Methods From March 2013 to October 5,5 cases of serum-immunoglobulin E level in young ischemic stroke adults with unknown etiology of abnormal IgE in our hospital were prospectively collected. The patients were divided into IgE normal group(18 cases)and IgE abnormal group (17 cases)according to the level of IgE. It observed inflammatory cells infiltration and mast cells by HE staining and toluidine blue staining respectively and determined the expressions of matrix metalloproteinase-9(MMP-9), monocyte chemotaxis protein-1 (MCP-1) and serum IgE by immunohistochemistry. Results The number of cerebral artery stenosis was 31 in the IgE normal group, and it was 36 in the IgE abnormal group. The distribution of stenosis showed that the narrow lesions of two groups was concentrated in the middle cerebral artery and internal carotid artery. There were 3 cases with outer membrane inflammatory cell infiltration(16.67%) in the IgE normal group, and it was 11 cases (64.71%) in the IgE abnormal group. There was significant difference between the two groups (P=0.004). Compared with IgE normal group, the mean optical density of MMP-9 and MCP-1 in IgE abnormal group were higher(P=0.4,0.02). Conclusion Abnormal serum-immunoglobulin E level in young ischemic stroke adults with unknown etiology should focus on the possible presence of inflammatory vascular disease.