Erythema infectiosum, also known as fifth disease, is a viral infection caused by the parvovirus B19. It primarily affects children and is characterized by a distinctive red rash on the cheeks, often described as a "slapped cheek" appearance. The rash may spread to the body and limbs, and the illness can also cause mild flu-like symptoms, such as fever and fatigue. The infection is usually mild and self-limiting, meaning it often resolves without treatment. Erythema infectiosum is contagious and spreads through respiratory droplets or direct contact with an infected person. While most healthy individuals recover fully, it can pose risks for pregnant women and those with certain blood disorders.