There are several different infections that can affect the ear, including fungal infections. Some of these can be treated with simple home remedies; however some do require medical attention. The physicians who would be well qualified to discuss this issue with you include your primary care doctor
The most common visible infection of the ear is an infection of the ear canal. This is called 'otitis externa' or, sometimes, 'swimmers ear.' As you say, otitis externa can be caused by fungal infections, but it can also be caused by bacteria. It is difficult to distinguish between these, as both are characterized by itching and sometimes pain of the ear, with drainage of material from the canal. Otitis externa is unlikely to spread to other parts of the body.
Sometimes otitis externa can be treated with home remedies, such as good ear cleaning and hydrogen peroxide. However, if there is worsening pain or itching or more drainage despite these methods, then there are several medicated ear drops that your doctor can prescribe.
As always, the diagnosis and the management of your specific condition will require a physical examination by your personal physician. Scheduling an office visit with your primary care doctor is highly recommended.