Patients with hearing loss in the left ear may have a variety of different causative factors or influencing factors, such as conductive hearing loss, mixed hearing loss, sensorineural hearing loss, etc. Patients need to pay attention to a careful and comprehensive examination of the ear to further clarify the cause of the disease, the main causes are ear canal blockage, inflammation and other factors, as follows: 1. The hearing loss may be caused by the blockage of cerumen in the ear canal. 2. Inflammation: Some patients may suffer from acute and chronic purulent otitis media, secretory otitis media, etc., resulting in conductive or mixed hearing loss. 3. Other factors: Some patients may suffer from sensorineural hearing loss due to long-term exposure to noise, excessive use of headphones, or age-related inner ear function degeneration, etc. Some patients may have sensorineural hearing loss, and some patients may even have sudden deafness.