Rosh Pediatrics Practice Exam

What pathogen is responsible for causing hand, foot, and mouth disease in a 4-year-old girl with vesicular lesions?

1. Coxsackievirus

2. Herpes simplex virus

3. Parvovirus B19

4. Treponema pallidum

The correct answer is: Coxsackievirus

Hand, foot, and mouth disease is primarily caused by the Coxsackievirus, particularly the Coxsackievirus A16 strain. This viral infection is characterized by the appearance of vesicular lesions on the hands, feet, and inside the mouth, which align with the symptoms presented in the question regarding the 4-year-old girl. Coxsackievirus is a member of the enterovirus family and often spreads among young children, especially in settings like daycare. While other pathogens are mentioned, they do not typically cause hand, foot, and mouth disease. For instance, Herpes simplex virus can cause vesicular lesions, but these are usually localized to the mouth or genital area and are associated with lesions that are painful rather than the multi-locational presentation seen in hand, foot, and mouth disease. Parvovirus B19 is primarily known for causing fifth disease, characterized by a distinctive rash, and Treponema pallidum is the causative agent of syphilis, which does not present with vesicular lesions in this pattern. Thus, the association of vesicular lesions with Coxsackievirus makes it the correct answer for this particular clinical scenario.