过敏性皮肤病是皮肤科常见病，其病因复杂，迁延反复，难以取得满意的疗效。过敏煎出自名老中医祝谌予，后世在“以皮治皮”理论的指导下，利用加味过敏煎（过敏煎+蝉蜕、白鲜皮）治疗过敏性皮肤病取得了满意的疗效。研究表明，PAR-2是肥大细胞脱颗粒信号自身放大机制的关键分子，也是导致瘙痒重要分子。课题组前期研究结果发现，加味过敏煎具有较好的缓解瘙痒作用，其机制可能与降低PAR-2表达，抑制肥大细胞脱颗粒有关。基于前期研究，提出以下假说：“以皮治皮”理论指导下加味过敏煎通过干预肥大细胞PAR-2表达，调控PAR-2/TPRV1信号途径，抑制肥大细胞脱颗粒“瀑布”效应，达到缓解过敏性皮肤瘙痒效果。本课题从肥大细胞脱颗粒、PAR-2的表达、PAR-2/TPRV1信号转导等3个方面，探索加味过敏煎治疗过敏性皮肤病瘙痒的靶点及具体机制，揭示“以皮治皮”理论科学内涵，为中医取象比类法理论的现代研究提供新的思路。

Allergic dermatosis is the most common disease in dermatology, and is protracted and repeated with a complex etiology. It is often difficult to achieve satisfactory results in treatment. “Guominjian Decoction” was created by Zhu-Shenyu, a famous old Chinese medicine practitioner, and “Modified Guominjian Decoction”（Guominjian Decoction+Periostracum Cicada and Cortex Dictamni） has obtained significant curative effect on treatment of allergic skin diseases under the guidance of the theory of “Treating skin diseases with skin drugs”. Recent studies have shown that PAR-2 is a key molecule of the self-amplification mechanism of mast cell degranulation signal and an essential molecule of itching.Our previous study found that “Modified Guominjian Decoction” has better anti-allergic effect and inhibits the degranulation of mast cells, and the mechanism may be related to PAR-2. Based on the research status at home and abroad and our previous research, the following hypothesis is put forward: Under the guidance of "Treating skin diseases with skin drugs" theory, "Modified Guominjian Decoction" can alleviate allergic skin pruritus by interfering with the expression of PAR-2 in mast cells, regulating PAR-2/TPRV1 signaling pathway and inhibiting the "waterfall" effect of mast cell degranulation. This study explores the target and mechanism of “Modified Guominjian Decoction” in treating pruritus of allergic skin diseases from three aspects:degranulation of mast cells, the expression of PAR-2 and the PAR-2/TPRV1 molecular signal path of mast cells. Is can disclose the nature of “Treating skin diseases with skin drugs” and promote the clinical application of dermatological intuitionism.