Through an analysis of the pathogenesis of cholinergic urticaria and the therapeutic principle of "treating fire constraint by dispersing it"， it is proposed that the disease is located between the sweat pore and interstitial space. The key pathogenesis lies in fire constraint in the interstitial space and stagnation of the sweat pore. The manifestation is rash due to fire-heat constrained in the interstitial space， while the root is the obstruction of

qi

and fluids in the sweat pore， and the transformation involves constraint fire damaging

yin

and entering the collaterals. Treatment should consistently follow the principle of "diffusing constraint and dissipating fire"， with staged approaches based on disease progression. In the acute stage， treatment emphasizes activating sweat pore and rapidly dispersing constraint fire through modified

Shengjiang Powder

（升降散）. In the remission stage， therapy should focus on harmonizing

ying

-

wei

（营卫） and clearing residual fire using modified

Zhuye Shigao Decoction

（竹叶石膏汤） combined with

Xiaofeng Powder

（消风散）. In the chronic stage， treatment should nourish

yin

， penetrate collaterals and clear latent fire through modified

Qinghao Biejia Decoction

（青蒿鳖甲汤）.