Fungal otitis externa and bacterial otitis externa are different in terms of causes and symptoms, which can be used to distinguish the type of disease; bacterial culture and smear test can clarify whether it is caused by fungal or bacterial infection. 1. Causes: Fungal otitis externa is mostly caused by continuous swimming, or the use of antibiotic drugs. Bacterial otitis externa can be caused by a variety of factors, such as damage to the external auditory canal, prolonged wearing of earphones, and pus irritation from otitis media. Therefore, during the consultation, the health care provider can make a preliminary judgment of the causative agent from the cause. 2. Symptoms: Fungal otitis externa and bacterial otitis externa can cause different degrees of hearing loss. However, fungal otitis externa is characterized by stuffiness, itchiness, and a large amount of black mass-like discharge. In contrast, bacterial otitis externa is characterized by purulent discharge and localized pain. 3. Bacterial culture and smear examination: Through bacterial and fungal culture, as well as smear examination, it is clear whether it is a bacterial or fungal infection through the colonies of culture and the mycelium of smear. There are different kinds of pathogens of otitis externa, and the treatment drugs used will be different. Therefore, it is important not to blindly use medication based on your own experience, but to seek medical attention and follow your doctor’s instructions.