Acute infectious urticaria, a subset of acute urticaria, with severe persistence wheals and systemic symptoms, response well to corticosteroids treatment in combination with antibiotics. The exact pathogenic mechanisms are not fully understood. In this study, we aim to analyze the different clinical features, compare the level of neutrophil activation, and investigate the expression of inflammatory related cytokine in patients with acute urticaria and acute infectious urticaria. Eighteen patients with acute infectious urticaria and eighteen patients with acute urticaria were included in this study. We analyzed the difference between the clinical features and the serum expressions of pro-inflammatory factors in the two groups, then examined the levels of inflammation-associated cytokines before and after treatment of acute infectious urticaria. Hematoxylin & eosin (HE) staining and immunohistochemistry (IHC) were used to further study the relationship between neutrophil and neutrophil-derived Myeloperoxidase (MPO) of lesions in the two groups. The expression levels of C-reactive protein (CRP), D-dimer, interleukin 6 (IL-6), IL-8 and chemokine ligand 8 (CCL8) in serum were significantly higher in acute infectious urticaria than acute urticaria. In acute infectious urticaria, the serum expression levels of CCL8 were significantly decreased after the treatment, a significant correlation observed between CRP levels and IL-6, both CCL8 and CRP were positively correlated with neutrophil granulocytes. Neutrophils infiltration were not observed by HE stains in two groups, but in IHC stains we found a positive expression of MPO in acute infectious urticaria lesions. Elevated neutrophil in the serum, which is associated with the levels of IL-8 & CCL8, and positively expressed MPO in lesions, may be involved in the pathogenic mechanism of acute infectious urticaria.

急性传染性荨麻疹是急性荨麻疹的一个亚型，具有严重的持续性风团和全身症状，对皮质类固醇联合抗生素治疗反应良好。确切的致病机制尚不完全清楚。在本研究中，我们旨在分析急性荨麻疹和急性感染性荨麻疹患者的不同临床特征，比较中性粒细胞活化水平，并探讨炎症相关细胞因子的表达。本研究纳入了 18 名急性传染性荨麻疹患者和 18 名急性荨麻疹患者。我们分析了两组患者临床特征及血清促炎因子表达量的差异,并检测了急性感染性荨麻疹治疗前后炎症相关细胞因子的水平。采用苏木精-伊红（HE）染色和免疫组织化学（IHC）进一步研究两组病灶中性粒细胞和中性粒细胞源性髓过氧化物酶（MPO）之间的关系。急性感染性荨麻疹患者血清中C反应蛋白(CRP)、D-二聚体、白细胞介素6(IL-6)、IL-8和趋化因子配体8(CCL8)的表达水平显着高于急性荨麻疹患者。急性感染性荨麻疹患者治疗后血清CCL8表达水平显着降低，CRP水平与IL-6呈显着相关性，CCL8和CRP均与中性粒细胞呈正相关。两组HE染色均未观察到中性粒细胞浸润，但IHC染色发现急性感染性荨麻疹皮损处有MPO阳性表达。血清中性粒细胞升高，与IL-8、CCL8水平相关，病灶内MPO阳性表达，可能参与急性传染性荨麻疹的发病机制。