<prompt> Commonest cause of Eustachian tube disease isAdenoidsSinusitisOtitis mediaPharyngitis  <response>: Adenoids cause eustachian tube dysfunction by a Mechanical obstruction to tubal opening b Acting as a reservoir for pathogenic organisms c In case of allergy, mast cells of the adenoid tissue release inflammatory mediators which cause tubal blockage Ref: Textbook of diseases if ENT, PL Dhingra, 7th edition, pg no. 64 