Final answer:
The symptoms described are consistent with roseola, a disease characterized by initial cold-like symptoms, a high fever, and a maculopapular rash starting on the trunk caused by HHV-6.
Step-by-step explanation:
The scenario describes a 2-year-old with a fever of 105°F followed by a pink maculopapular rash on the trunk, arms, and legs three days later. The described symptoms suggest the child may be diagnosed with roseola, based on the high fever followed by a maculopapular rash that starts on the trunk and spreads. Roseola is caused by human herpesvirus-6 (HHV-6) and is characterized by initial cold-like symptoms and a high fever, followed by the characteristic rash.
In contrast, Fifth disease, caused by parvovirus B19, would typically present with a "slapped cheek" rash on the face rather than the rash beginning on the trunk. Other childhood diseases, such as measles, would present with additional symptoms such as Koplik's spots on the oral mucosa, and chickenpox would involve pustular lesions rather than a maculopapular rash.