They are not disease specific and are most commonly seen in chronic cases. These factors may be subtle at first but can develop into the most severe component of chronic ear disease. In many cases, perpetuating factors prevent the resolution of otitis externa when treatments are directed only at primary and secondary causes. 1,2 Once present, they accentuate or permit the development of secondary causes, such as infection, by providing favorable environments and microscopic niches.
Perpetuating factors sustain and aggravate the inflammatory process and prevent resolution of, or worsen existing, otitis externa. It is important to eliminate as many of these factors as possible while realizing that some, such as ear conformation, cannot be changed. 1,2 In conjunction with primary or secondary causes, these factors become a significant problem. Predisposing factors alone do not cause otitis externa, but they facilitate inflammation by permitting the external ear canal microenvironment to be altered, thereby allowing pathogenic or opportunistic bacteria or yeast to become established. When they are chronic and difficult to treat, it is usually because primary causes or perpetuating factors have not been adequately addressed. 1–3 Generally, secondary causes of otitis externa are easy to eliminate once identified. The most common secondary causes are infections. Secondary causes occur in combination with primary causes or predisposing factors.
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