There may be various reasons that lead to obstructive hearing loss, but these commonly include:
Drugs - including certain antibiotics and cancer drugs, can damage some of the hearing nerves or the sensory cells of the cochlea, and therefore lead to otitis media (a group of inflammatory diseases of the middle ear).
Problems affecting the external ear canal, eardrum, middle ear bones, or middle ear space.
Chronic diseases or trauma can cause the eardrum to burst, or the middle ear bones to be dislodged, damaged or fixed.
Middle ear infections, also known as otitis media. Otitis media occurs due to a variety of causes including increasing age, inner ear viral and bacterial infections (mumps, measles, influenza), ménière disease (inner ear disorder that affects balance and hearing), and damage to the sensory cells in the cochlea due to acute or chronic exposure to loud noises.
Blockage due to wax or foreign objects, which can also lead to infection.