I'm not a Chinese herbalist, but the treatment begins with Ma Huang, botanical name Ephedra, from which ephedrine is extracted, from which pseudoephedrine is synthesised.
It stimulates the kidneys and adrenals, flushes allergens from the body, mimics adrenalin, and in so doing, opens the airways.
After that it gets complicated, but it's to do with retraining the body to not respond to allergens.