What really causes conductive hearing loss?

Conductive hearing loss is caused by anything that blocks the transmission of sound waves on their passage from the outer to the inner ear. Here are some examples of situations that can cause conductive hearing loss.

Sometimes, head injury or other accidental trauma damages the structures of the outer or middle ear. Most common is a perforated eardrum, where the delicate membrane dividing the outer from the middle ear is damaged.

This can happen as a result of a blow to the ear or rapid pressure changes when flying or scuba diving. The pressure blast of an explosion or other very loud noise can also contribute. Another culprit is a buildup of fluid pressure due to untreated middle ear infection. Very often, misguided attempts to clear wax from the ear canal can also result in a perforated eardrum.

A perforated eardrum may cause short-term pain, temporarily reduced hearing and sometimes a discharge, but it usually heals on its own within a few weeks. In the meantime keep your ear dry, as water from showering or swimming could lead to infection and permanent damage.

A buildup of wax or a foreign body lodged in the ear canal dulls your hearing because the sound waves can't reach the eardrum. Wax is there for a reason; it's stickiness traps dirt, dust and germs, and contains lysozyme, the natural antibacterial substance present in tears.

But sometimes you can end up with a lump of wax that interferes with hearing. Never push cotton swabs deep into your ear — not only could you damage the eardrum but you may also push the wax and compact it against the drum. Visit a clinic where a health professional will check your ears for wax and clean them if need be.

Ordinary coughs, colds, flu, tonsillitis and sinusitis can lead to fluid buildup and swelling or blockage of the Eustachian tubes. This often leads to muffled hearing and can cause tinnitus. There may also be earaches and a raised temperature.

Allergies and enlarged adenoids can have a similar effect. When fluid builds up in the middle ear and gets infected, it's known as otitis media — a common complaint in young children because their short, horizontal Eustachian tubes make them more susceptible.

In rare instances, repeated ear infections can lead to collapse of the eardrum. This can form a retraction pocket in the middle ear. Trapped skin cells may become infected and create a cyst (cholesteatoma). Left untreated, the cyst can grow and damage the middle ear structures, causing hearing loss and dizziness.

Other symptoms include a sensation of fullness in one ear, a smelly discharge, and nighttime earaches in or behind the ear. There may even be muscle weakness on the side of the face closest to that ear.

This rare condition is a result of abnormal bone growth. It's when one (or more) of the ossicles in the middle ear becomes less mobile. Then it cannot transmit sound vibrations properly.

Otosclerosis can also cause dizziness, balance disorders and tinnitus. The condition often runs in families and affects more females than males. The hearing loss often becomes apparent during or following pregnancy.