Eustachian tubes are small tubes that run between the middle ears and the upper throat . The primary function of the Eustachian tube is to ventilate the middle ear space, ensuring that its pressure remains near normal environmental air pressure . The secondary function of the Eustachian tube is to drain any accumulated secretions, infection, or debris from the middle ear space . Several small muscles located in the back of the throat and palate control the opening and closing of the Eustachian tube . Swallowing and yawning cause contractions of these muscles located in the back of the throat and help regulate Eustachian tube function. If it weren’t for the Eustachian tube, the middle ear cavity would be an isolated air pocket inside the head that would be vulnerable to every change in air pressure and lead to unhealthy middle ear space function .
People with some Eustachian tube dysfunction (ETD) may experience signs and symptoms, such as; [1, 2]
Intermittent ear fullness
Ear-popping or cracking
Mild hearing sound (an attenuation of sound
Ringing in the ears (tinnitus) and
Occasionally poor balance
The Eustachian tube can be blocked, or obstructed, for a variety of reasons, for example: 
The most common cause is a cold (upper respiratory infection)
Sinus infections and allergies may also cause swelling of the tissue lining the Eustachian tube. Simply put, a stuffy node leads to stuffy ears.
Children are particularly prone to Eustachian tube blockage because their tubes are narrower in diameter, more horizontal in orientation, and closer at the nasal opening of the Eustachian tube to the adenoids
Adenoid tissue in the back of the nose near the Eustachian tube can act as a reservoir for bacteria, contributing to recurrent ear infections. Enlarged adenoids obstructing the opening of the Eustachian tube may also be present. Adenoid removal (adenoidectomy is frequently recommended in children with chronic ear infections (chronic otitis media)
Rarely, masses or tumors in the skull base or nasopharynx can lead to Eustachian tube obstruction
Excessively small Eustachian tubes (as may afflict children with down syndrome)
Smoking is associated with damage to the cilia that sweep mucus and debris from the middle ear space via the Eustachian tube to the back of the nose where it may be expelled.
Causes of Eustachian tube dysfunction range from allergies to excessively small Eustachian tubes (as may afflict children with Down syndrome).
ETD is diagnosed through a physical examination . First, the doctor will ask about pain, hearing changes, or other symptoms you are experiencing. Then the doctor will look inside the ear, carefully checking your ear canal and passages into the nose and throat. Sometimes ETD may be mistaken for other conditions involving ears such as abnormal patency of the Eustachian tubes, which is a condition where the tubes frequently open on their own .
Several maneuvers may be done to improve the Eustachian tube function and thus aid in the equalization of air pressure .
The simple act of swallowing activates the muscles in the back of the throat that help open the Eustachian tube. Any activity that promotes swallowing can help open the Eustachian tube, for example chewing gum, drinking, or eating.
Yawning is even more effective because it is a stronger muscle activator.
If the ears still feel full, the person can try to forcibly open the Eustachian tube by taking a deep breath and blowing while pinching your nostrils and closing the mouth. When a “pop” is felt, you know you have succeeded. If problems persist despite trying to forcibly open the tubes you may need to seek medical attention.
If you have a cold, sinus infection, ear infection, or suffering from allergies, it may be advisable to postpone air travel.
Similarly, individuals with Eustachian tube problems may find such sports as scuba diving painful, and in some situations quite dangerous.
Babies traveling on airplanes cannot intentionally pop their ears but may do so if they are sucking on a bottle or pacifier. Crying, similar in function to yawning, will also enable equalization of air pressure.
ETD is usually resolved without treatment. But if the symptoms are severe or persist for more than two weeks, talk to the doctor about treatment options.
Treatment for ETD depends on both the severity and cause of the condition and may include home remedies, over-the-counter medications, and prescription drugs for allergies such as diphenhydramine and pain relievers like acetaminophen and ibuprofen .
In the case of an infection, the doctor may prescribe an antibiotic. This can come in cases of severe inflammation . Severe cases of ETD may require more invasive treatments. Pressure equalization tubes (PETs) are implanted in some people to equalize ear pressure to help with frequent or chronic middle ear infections [1, 2]. Built-up fluids may also need to be drained if the Eustachian tube is not functioning properly. This is done by making a small cut in the eardrum to help fluid drain .
The most common complication of ETD is the risk for recurring symptoms that usually come back when the underlying causes of ETD are not treated. These include; 
Chronic otitis media (middle ear infection)
Otitis media with effusion is often called ear glue. This refers to fluid buildup in the middle ear. It may last for a few weeks, but more severe cases can cause permanent hearing damage.
Eardrum retraction, which is when the eardrum is seemingly sucked back further into the canal.
ETD is a relatively common condition that usually resolves on its own. The length of time that ETD symptoms last depends on the initial cause. Symptoms from altitude changes, for example, may resolve once you get back to the altitude you’re used to. Illnesses and other causes of ETD may result in longer-lasting symptoms .
1. Eustachian Tube Dysfunction: Symptoms, Causes, and More. Available at https://www.healthline.com/health/eustachian-tube-dysfunction#causes. Access on 15th July 2021.
2. Eustachian Tube Dysfunction: Treatment, Causes, Surgery & Healing Time. Available at https://www.medicinenet.com/eustachian_tube_problems/article.htm. Accessed on 15th july 2021.