Updated on 6/30/2005
Fifth disease is a common infection among children. It's caused by the human parvovirus B19. This virus isn't the same as the parvovirus that affects cats and dogs, which does not affect humans. (Children can't catch the virus from a pet, and cats and dogs can't become infected by the virus that infects humans.)
It's called "fifth" disease because it's the fifth of the six common rash-producing diseases that doctors used to see in children. (The first was measles, the second was scarlet fever, the third was rubella, the fourth was called Duke's disease, which has never been distinguished from other rash-related childhood illnesses, and the sixth was roseola.)
Fifth disease is a mild illness that causes a rash on the cheeks that looks like the child's face has been slapped. It also causes a lacy red rash on the trunk, arms, and legs. Occasionally the rash itches, and sometimes the child has a low-grade fever, feels listless, or has a cold a few days before the rash appears. The illness runs its course in seven to 10 days, during which time children usually don't feel very ill.
The infection is contagious before the rash appears, but once it does, youngsters usually can't pass on the virus. This pattern is the opposite of other childhood diseases such as measles, which is contagious when the rash is present, not before. With fifth disease, the infection spreads by respiratory secretions passed on by direct contact such as sharing drinking cups or utensils.
My colleague John Mark, M.D., a pediatrician at the University of Arizona's Arizona Center for Integrative Medicine, tells me that fifth disease isn't a problem among healthy children. However, it can lead to serious illness among youngsters with sickle-cell disease or related types of chronic anemia. Usually, after children have had fifth disease, they're immune to it. If your child has had no previous health problems or recurrent infections, the second episode your daughter had was probably something else. As long as she is otherwise healthy, Dr. Mark suggests using echinacea to enhance her immunity. He recommends using an alcohol-based tincture. The dose for a seven-year-old would be one milliliter two to three times a day. Echinacea works best to stimulate the immune system when taken on a short-term basis at the first sign of illness and until symptoms subside.
Andrew Weil, M.D.