Final answer:
The APRN should suspect roseola infantum in the 8-month-old with initial cold-like symptoms and high fever followed by a rash, performing a thorough examination and monitoring the fever. Treatment is usually not necessary as the condition often resolves on its own, but immunocompromised individuals may require antiviral medication. Education for the parents on disease course and comfort care is also important.
Step-by-step explanation:
The appropriate action for the Advanced Practice Registered Nurse (APRN) to take when an 8-month-old presents with a history of fever for 5 days followed by an erythematous, macular rash on his trunk, neck, and arms is to consider a viral illness such as roseola infantum. Given the initial cold-like symptoms with high fever, followed by a macular or papular rash three to five days later, roseola caused by human herpesvirus-6 (HHV-6) is likely.
The APRN should conduct a thorough examination, confirm the signs and symptoms, and consider the child's medical history and any recent exposure to infectious diseases. While treatment for roseola is usually not necessary, as the disease typically resolves without treatment, the APRN will monitor the child's fever and suggest measures for fever management. In certain cases, especially for immunocompromised individuals, antiviral medication like ganciclovir may be used.
If the diagnosis is unclear or if there is a concern for another etiology, additional serological tests might be warranted. It's also important to educate the parents on the typical course of the disease, what signs to watch for that would necessitate a return visit, and ways to keep the child comfortable.