My son is 5 years and is allergic to dust and has asthma. what are the advantages and disadvantages of having his tonsils and adenoids removed.

Unnecessary: The palatine tonsils & adenoids are part of the immune system.They tend to grow faster than the kid up to the age 6-8, stabilize & stop.The kid then continues to grow while T&A become comparatively smaller as they do. The few real indications for removal include chronic tonsil infections (5+/yr) & sleep apnea. Such an operation would never be approved/paid by insurers in the US for asthma/allergy