Sudden blockage in one ear can be caused by inflammation or neurological problems. Inflammatory ear blockage can be caused by inflammation of the external auditory canal, otitis media, mastoiditis, etc. In some cases, the only outlet of the ear, the eustachian tube, is inflamed or blocked, resulting in an imbalance of atmospheric pressure inside and outside the eardrum, causing a feeling of ear stuffiness and blockage. In some patients, the sudden blockage of the ears is mainly caused by sudden deafness, because of the sudden loss of hearing, the sensation of ear congestion is very obvious, and many of them will have tinnitus and vertigo symptoms.