How is inflammation or blockage of eustachian tube determined and then treated?

ENT doc 4 evaluation: Use decongestant to reduce swelling of tube linine; take antihistamine or use steroid nasal spray to reduce allergic response if allergies are factor; place pressure equalization tubes (PETs) in eardrums to equalize ear pressure; make tiny incision in eardrum/suction out the fluid in middle ear. This gives the eustachian tube lining time to shrink while the eardrum is healing (usually 1 to 3 days)