Causes of deafness and hearing loss

Around half of deaf children are born deaf. This is called congenital deafness. Congenital deafness is often caused by genetic factors. This means that the child has a gene variation which affects their hearing.

Genetic deafness can be:

• syndromic (where the gene variation causes a collection of related symptoms)
• non-syndromic (where the gene variation is only known to cause deafness)

Genetic deafness can be inherited (passed down through families). However, most children with genetic deafness do not have any family history of deafness.

Find out more about genetic causes of deafness.

Congenital deafness can also be caused by an infection during pregnancy, such as cytomegalovirus (CMV). This is the second most-common cause of congenital deafness in the UK.

Other types of infection which can cause deafness in unborn babies include rubella, toxoplasmosis and herpes.

Some babies become deaf shortly after birth. This is especially common in premature babies who may:

• develop an infection which causes deafness
• be treated with ototoxic medication (medicine which causes deafness as a side-effect)

Severe jaundice (yellowing of the eyes and skin) or a lack of oxygen during birth can also cause deafness.

Around half of deaf children are born hearing but become deaf during childhood. This is called acquired deafness.

The most common cause of acquired deafness in children is glue ear. Glue ear is a common childhood condition where fluid builds up in the middle ear, causing temporary hearing loss.

Acquired deafness can also be caused by:

• infections like meningitis, measles, mumps and rubella
• head injuries
• exposure to loud noises
• some medications, such as chemotherapy

Some genetic causes of deafness are associated with progressive deafness. Children are born hearing but become deaf during childhood or later in life.

Ototoxic drugs used in medical treatments

Ototoxic drugs (drugs that can cause damage to the inner ear) used in some medical treatments can cause hearing loss, tinnitus and balance problems.

Children being treated for cancer are at particular risk of hearing loss caused by the cisplatin-based chemotherapy agents used in childhood cancer treatment. Children having chemotherapy should have regular hearing tests to check for any changes early, so that oncologists (cancer doctors) can consider alternative drugs or changing treatment doses. Hearing aids can also be offered if needed.

RNID have more information about deafness caused by ototoxic drugs.