Causes of Hearing loss

Congenital causes. These occur while the baby is developing. Hearing loss can be hereditary or due to complications during pregnancy and childbirth. These can cause hearing loss when born or shortly after. Notably: 

• Maternal rubella, syphilis or other maternal infections during pregnancy. 
• Prematurity and/or low weight of the baby at birth. 
• Perinatal asphyxia (a lack of oxygen during childbirth).
• Inadequate use of certain medications, such as aminoglycosides, cytotoxics (for cancer treatment), antimalarials and diuretics. 
• Severe jaundice (due to liver, gallbladder or pancreas failure in the baby) that can injure the auditory nerve. 

Acquired causes. These can trigger hearing loss at any age. Among the most frequent are those affecting:  

Outer and middle ear 

• Obstruction of the ear canal with cerumen (wax) or a foreign body.
• Liquid in the middle ear due to a malfunction of drainage from the nose (serous otitis media). 
• Acute repeated infections or otitis or chronic otitis that damage the outer and middle ear. 
• Trauma, due to using cotton buds or similar to clean wax from the ear. 

Inner ear and nerve pathways  

• Certain infectious diseases, for example, meningitis, measles or mumps.
• The use of certain medications.
• Traumatic head injuries.
• Exposure to excessive noise.
• Ageing, which leads to the degeneration of sensory cells. 

Age. Over time, the internal structures of the ear and brain degenerate. 

Exposure to loud noises. Inner ear cells can be damaged by exposure to loud noise in a short period of time (e.g., a gunshot or fireworks explosion) or by prolonged exposure to noise (e.g., working in a noisy environment without proper protection or continuously listening to music at a high volume). 

Hereditary factors. A certain genetic makeup may make some people more susceptible to damage caused by loud noises or greater deterioration as they get older.

Medication. Certain medications are damaging for the ear either temporarily or definitively. These are called ototoxic products. Among the most common are certain antibiotics (e.g., aminoglycosides), drugs for cancer treatment (chemotherapy) or for the prophylaxis and treatment of malaria (quinine).  

Alcohol and tobacco. These substances are also considered ototoxic. 

Certain diseases. Some infectious diseases, such as meningitis or measles, which cause high fevers, can damage cochlea cells.