By the way, doctor: Plugged-up feeling in an ear

Q. My left ear feels clogged. . It usually starts about 4 p.m. and lasts about three to four hours. I cough, clear my throat, yawn, close my nostrils and blow — nothing seems to help my ear to feel less clogged.

A. It seems like your ear has been feeling clogged for a while, so my first suggestion is to see a doctor and start the process that would lead to a diagnosis and proper treatment.

The diagnosis of almost any ear problem starts with a few basic questions. One of the most obvious is also one of the most important: have you lost any hearing? Sometimes people experience hearing loss as a plugged-up feeling, so some tests may be necessary to sort that issue out.

Doctors also ask patients with clogged ears about dizziness, pain, ringing in the ears, or fluid discharge. The answers help steer testing and other diagnostic detective work. Ear problems with dizziness — the room-spinning kind that's the main feature of true vertigo — might merit investigation into whether someone has Ménière's disease, an uncommon condition caused by an imbalance of fluid in the inner ear. Ear pain is a good clue that the problem is a middle ear infection. Ear pain with a moist discharge is a common symptom of swimmer's ear.

How to unclog your ears

Other important questions: Are both ears affected or is it just one ear that feels clogged? Did the symptoms come on suddenly or gradually? Do they persist or come and go?

Your ear may feel clogged simply because it is filled with earwax. I can't explain the regular late-afternoon onset, but earwax blockages can come and go. They can get worse after a shower, for example, because the wax soaks up water. As tempting as it might be, don't try to remove earwax yourself. Cotton swabs and pencil erasers can break off in the ear canal, which isn't the straight passageway that it appears to be from the outside but one that bends and narrows. Let a doctor take a look.

Another possibility is that you have eustachian tube dysfunction. You can't see the eustachian (pronounced you-STAY-shun) tube. It's entirely inside your head, connecting the middle ear to the nasopharynx, the area at the very back of the nasal cavity near where it joins the throat (see illustration). In adults, the eustachian tube is a little over an inch long and runs forward and downward from the middle ear to the nasopharynx. It's made of cartilage and bone and is lined with a moist, mucous membrane.

Normally, the eustachian tube helps equalize air pressure on either side of the eardrum by allowing air to flow in and out of the middle ear. If it gets blocked, then there's less pressure in the middle ear, which creates a little suction, so the eardrum gets pulled inward. This causes a full, plugged feeling in the ear and also makes the eardrum less able to vibrate, so hearing will seem a little off. If the blockage is severe and lasts a while, the low pressure in the middle ear can pull fluids out of the surrounding tissue and blood vessels, so the middle ear fills up with fluid.

A cold or allergies can cause the lining of the eustachian tube to swell shut. And in situations when the air pressure is changing rapidly, as it does when you're in an ascending or descending airplane, your eustachian tubes must function well to keep the air pressure on either side of the eardrums the same. When you blow out with your mouth closed and your nostrils squeezed shut to "pop" your ears, you're forcing air up the eustachian tubes and bringing the air pressure back into equilibrium.

Some people have eustachian tubes that don't function very well, so they get the plugged-up ear sensation rather easily from a cold or during airplane travel or without any apparent precipitating event. This may be your problem.

Bad cases of eustachian tube dysfunction can be treated by inserting little plastic tubes into the eardrum to aerate the middle ear from the external ear canal, rather than depending on the eustachian tube to do the job.

If the plugged-up feeling is constant and is affecting only one ear, then a doctor needs to check the opening of the tube in the nasopharynx to make sure it isn't blocked by a tumor.

If the plugged-up feeling comes and goes, you can try a non-prescription decongestant or antihistamine.

Image: KatarzynaBialasiewicz/Getty Images