XXXII The Pathology of Acute Diffuse External Otitis

Abstract

Acute inflammations of the skin of the external auditory canal occur frequently in hot, humid environments and have been variously named diffuse external otitis/ furunculosis, fungous ear, desquamative otitis externa.f tropical otitis externa," and hot weather ear." Although much has been written regarding the clinical picture and the bacteriologic flora associated with this disease, the pathogenesis of this entity remains a matter of controversy in medical literature.As part of an integrated investigation of the etiology, pathology, and treatment of the external ear, a histopathologic study of the affected skin seemed desirable. To our knowledge biopsy material from acute cases of diffuse external otitis has in the past never been obtained, although an occasional report describing chronic changes in the periauricular area is available."On the basis of earlier and preliminary pathologic data, the following concept of the pathogenesis of acute diffuse external otitis was suggested by one of the authors." 7 As a result of persistent high temperature and humidity, and wetting of the skin by swimming or bathing, there is produced in certain susceptible individuals a thickening of the stratum corneum. This results in the plugging of pilosebaceous units and the skin of the ear canal is deprived of its normal oily water-repellent protective coating. If the hot, humid period continues, there develops a pre-inflammatory state consisting of an itchy, dry, scaly skin, devoid of sufficient surface lipids. Such dry skin is constantly irritated by rubbing, scratching, and the application of irritating medications. Under such conditions the ubiquitous