American Board of Internal Medicine (ABIM) Certification Practice Exam

How does the rash typically progress in Rocky Mountain spotted fever?

1. It starts as a diffuse rash on the face.

2. It typically starts at the central body and moves outward.

3. It begins as macular and localized to wrists and ankles.

4. It appears as a large blistering rash.

The correct answer is: It begins as macular and localized to wrists and ankles.

In Rocky Mountain spotted fever (RMSF), the rash is a key clinical feature that aids in the diagnosis of the disease, which is caused by the bacterium Rickettsia rickettsii. The rash typically begins as small, flat, pink spots (macules) and is localized primarily to the wrists and ankles. This presentation is significant because it reflects the initial entry points of the pathogen, as well as its tendency to spread. As the disease progresses, the rash can become more widespread and may evolve into raised reddish bumps (petechiae) that can appear on the trunk and spread to other areas of the body. The characteristic progression starting at the extremities aligns with the understanding of how RMSF develops over time. Recognizing the typical onset of the rash's location is crucial in differentiating it from other rashes that may appear in a variety of other conditions. The other options do not accurately describe the typical progression of the rash in Rocky Mountain spotted fever. For instance, the rash does not begin as a diffuse rash on the face, nor does it typically start at the central body and move outward in this specific illness. Additionally, the presence of a large blistering rash is inconsistent with the typical rash that appears in