Some of the most common illnesses of childhood cause skin eruptions and are known as exanthems. The childhood exanthems include rubeola (measles), rubella (German measles), chicken pox, erythema infectiosum (fifth disease), and roseola infantum, all of which are viral infections, as well as scarlet fever, a bacterial infection. All of these infections affect the respiratory system and are highly contagious.

Children with these illnesses usually recover fully even without treatment; however, all of these conditions carry the possibility of severe complications, such as pneumonia, heart and kidney damage, and encephalitis (inflammation of the brain). Vaccinations and other changes in modern lifestyle have rendered several of these previously common illnesses virtually nonexistent in the developed world, though they are widespread and remain a major cause of childhood deaths in other parts of the world.