Adenoidal hypertrophy or enlargement in adults is much less commonly seen than in children. It is usually due to chronic infection or inflammation. HIV always needs to be excluded as a cause.
In general, the adenoid tonsils enlarge after birth, maximizing by 6 years old. Thereafter, the adenoids gradually involute and in most individuals can no longer be seen by 16 years old 1.
Causes of adenoidal hypertrophy in adults may include infections, inflammation and allergy: