What is a common cause of otitis externa?

A common cause of otitis externa, also known as swimmer's ear, is constant ear wetness. This condition arises when the exterior of the ear becomes damp repeatedly or remains wet, creating an environment conducive to bacteria or fungi growth. Moisture can result from swimming, bathing, or even excessive sweating. The warm and moist environment allows pathogens to thrive, leading to inflammation and infection of the ear canal.

While blocked ear canals, excessive earwax production, and narrowing of the ear canal can contribute to ear problems, they are not directly linked as common causes of otitis externa compared to constant exposure to moisture. Blockages and narrowing may cause issues with drainage but do not inherently lead to the infection like moisture does, which is why this option is focused on for understanding otitis externa's etiology.