Echinacea has value both for fighting infections and treating many allergies. Echinacea often is called an immune system booster. This is incorrect. It strenghtens the immune system to work properly. Fennel seeds often get used in both TCM and Western herbalism for treating allergies.
Allergies can have different TCM profiles.
There are more strategies for dealing with allergies, but I won't go into them in this post. Sometimes a person has chronic sinus problems because of structural problems. There are some TCM and other treatments which can be effective in some cases of nasal polyps, or the person may require surgery. Spinal misalignment can trigger head and sinus congestion. There is an adjustment to the neck that chiropractors and DOs can give which can open up nasal passages.