USMLE (United States Medical Licensing Examination) Step 1 Practice Exam

Malignant otitis externa is a severe and potentially life-threatening infection of the external auditory canal that typically occurs in elderly patients, particularly those with underlying conditions such as diabetes mellitus. This patient population is at higher risk because diabetes can impair immune function, leading to an increased susceptibility to infections, particularly from opportunistic organisms like Pseudomonas aeruginosa, which is often the causative agent in cases of malignant otitis externa.

In contrast, young adults, children, and pregnant women do not have the same level of vulnerability to this particular condition. Young adults and children generally have more robust immune systems, while pregnant women may have unique immunological changes but do not have the same risk factors associated with diabetes. Therefore, elderly diabetics represent the group most at risk for developing malignant otitis externa.