What is otitis externa? Otitis externa is an infection of the outer ear canal and the external ear, which is known as the pinna. Otitis externa is commonly known as swimmer’s ear. Otitis externa can develop when water remains in the outer ear canal, most commonly after swimming. Moisture within the warm confines of the ear canal creates a friendly environment for the growth of bacteria, such as Pseudomonas, which can migrate into the ear and cause an infection. In addition, the water itself may be contaminated with bacteria or other organisms. Common symptoms of otitis externa include itchy ears, redness of the outer ear, and pain that occurs when touching the ear or tugging on the earlobe. Other symptoms include yellow, greenish, or pus-like fluid draining from the ear and temporary hearing loss. Swimming is not the only cause of otitis externa. Even water remaining in your ears after showering may allow the development of an infection. Other causes can contribute to swimmer’s ear, including an infection of the bone at the base of the skull, a foreign object lodged in the ear, and irritation from itching or cleaning the ear. Allergies to earrings or inflammatory skin conditions, such as eczema, can also produce symptoms of swimmer’s ear. Symptoms of otitis externa should be evaluated by your health care provider. Seek prompt medical care if you experience any of the following symptoms, including fever; fluid draining from your ears; pain behind the ears; redness, burning, swelling or itching on or around the ear; or symptoms that persist despite treatment.