What common childhood viral infection is characterized by saddleback fever and a “slapped cheek” rash?

Fifth disease, also known as erythema infectiosum, is a common viral infection in childhood caused by parvovirus B19. It is most notably characterized by two key features: a distinctive “slapped cheek” rash and a saddleback fever pattern. The “slapped cheek” appearance typically involves bright red cheeks and may be accompanied by a lacy, reticular rash on the body, which can follow as the illness progresses. The name "fifth disease" originates from the historical classification of common childhood rashes.

The presence of saddleback fever refers to fluctuating fevers that rise and fall, which can occur during the course of the infection. In the context of this illness, the rash may appear as the fever subsides. Understanding these core symptoms helps distinguish Fifth disease from other viral infections.

In contrast, measles presents with a more extensive rash and spots known as Koplik spots, while rubella features a different kind of rash and other systemic symptoms. Chickenpox is characterized by a different pattern of vesicular rash and intense itching. The specific features of Fifth disease make it unique among these common viral infections in children.