American Board of Internal Medicine (ABIM) Certification Practice Exam

What symptom characterizes the rash of smallpox during its initial phase?

1. Begins as small macules on the torso

2. Begins as small red dots on the pharyngeal and buccal mucosa

3. Begins as vesicles on the extremities

4. Begins with a generalized rash on the legs

The correct answer is: Begins as small red dots on the pharyngeal and buccal mucosa

The characteristic symptom of smallpox during its initial phase is the presence of small red dots on the pharyngeal and buccal mucosa. This appearance is part of the prodromal stage of smallpox, which typically occurs about 2 to 4 days after exposure to the virus. During this phase, lesions known as enanthem develop in the mouth, specifically on the mucosal surfaces, and they resemble small red spots. The presence of these lesions is significant as they can be an early indicator of the disease. Following this prodromal period, the disease progresses to the classic exanthem phase, where the rash starts appearing on the skin. Understanding this progression is crucial not only for diagnosis but also for implementing appropriate infection control measures, given the contagious nature of smallpox. In contrast, the other options describe aspects of the rash or symptoms associated with either other diseases or incorrect stages of smallpox, highlighting the importance of recognizing the unique features of smallpox for effective identification and management.