Fifth Disease, also known as "erythema infectiosum," is a mild, self-limited viral infection. It most commonly occurs in children, and is characterized primarily by fever and a distinctive rash, usually over the cheeks. This distinctive rash is responsible for another name occasionally used for this disease, "slapped-cheek disease."
Fifth Disease is caused by human parvovirus B19, a DNA virus in the parvovirus family of viruses. This is the only virus in this family that causes disease in humans.
Parvovirus B19 predominantly infects school children. Children generally acquire an infection during the school months, until May and June. Epidemics occur approximately every six years, and last approximately three years.
Parvovirus B19 is transmitted from person-to-person by direct contact or by contaminated secretions of the nose and the mouth. Parvovirus B19 infects the lining of the nose and the upper respiratory tract. Then, it is spread through the blood throughout the body, which causes the rash. The virus also infects the bone marrow cells that are responsible for producing new red blood cells. This particular characteristic may result in complications in those persons who have an underlying anemia or other blood disorder.
Fifth Disease can be divided into four phases: 1) the incubation phase, 2) the prodromal phase, 3) the rash phase, and 4) the recovery phase. The incubation phase typically lasts 8 to 12 days after exposure to the virus and does not have any symptoms. During the prodromal phase, the symptoms are mild and include a headache, a low-grade fever, fatigue, and a sore throat. These symptoms usually last for a few days and then resolve. The rash that develops produces an intense rose-red color on both cheeks that does not involve the area around the mouth. This rash is often referred to as the "slapped cheek" rash because of its appearance. The rash usually lasts one to four days and then fades. On other parts of the body, a less prominent rash can occur at the same time or within one to two days. The chest, arms, and legs can develop a flat red rash that has a lace-like appearance.
Adults who get a parvovirus B19 infection are more likely than children to develop joint aches and pains. This typically develops at the time that the rash appears. The joint symptoms usually resolve within four months, but they may persist for a year or more.
The infection is usually diagnosed by the characteristic appearance of the rash in a child with a fever and no other symptoms. A blood test is available to confirm the infection; however, it usually is not necessary.
Specific treatment for Fifth Disease is not available. Antibiotics are not helpful because a virus causes Fifth Disease. Viruses cannot be treated with antibiotics. Fever and pain should be treated with acetaminophen or ibuprofen. The disease is usually mild with complete recovery.
Patients with underlying anemia may require a blood transfusion during the acute illness, but they then recover to their previous state of health.
Children who have underlying anemia are at risk for developing worse anemia with the parvovirus B19 infection. The virus infects the blood cells that produce red blood cells and causes a temporary decrease in the production of red blood cells. Some children require one or, occasionally, more transfusions. Usually, there is recovery within one to two weeks, with a return to normal blood counts within three to four weeks.
The parvovirus B19 infection in pregnant women can result in transmission of the virus to the fetus, and the bone marrow cells of the fetus are infected. This results in anemia in the fetus and leads to the condition known as "hydrops fetalis," which is associated with fetal heart failure and may cause fetal death and spontaneous abortion. However, even if a woman acquires the parvovirus B19 infection during pregnancy, chances for fetal survival are probably 90%. The virus does not cause birth defects or other problems if the fetus survives the period of the maternal infection.
A vaccine is not available for the human parvovirus B19 infection. Because of the widespread nature of the virus, there is no way to eliminate the risk of exposure. Healthy children with Fifth Disease can attend day care or school because they are most contagious before the rash, and are unlikely to be contagious after the onset of the rash.
Routine exclusion of pregnant women from the workplace or social events is not recommended. Pregnant women who find that they have been in close contact with children in the few days before the onset of the rash of Fifth Disease, or of children who had anemia from Fifth Disease, are at a low risk of infection and complications. Blood tests and fetal ultrasound can help assess the possibility of infection of the fetus.
Substantial research is currently being performed to develop a vaccine to prevent the human parvovirus B19 infection. If proved to be safe and effective, a vaccine could be administered to children early in life to prevent infection during childhood. The vaccine also could be administered during pregnancy to prevent the occasional fetal death that occurs from the parvovirus B19 infection.
About the Authors
Hal Jenson, M.D.
Dr. Jenson graduated from George Washington University School of Medicine in Washington, DC,
He also completed a residency in pediatrics at the Rainbow Babies and Children's Hospital of Case Western Reserve University in Cleveland, Ohio, and a fellowship in pediatric infectious diseases and epidemiology at Yale University School of Medicine.
Dr. Jenson has an active research program on the biology of Epstein-Barr virus and other human and non-human primate herpes viruses.
He is active in the general pediatric and infectious diseases teaching and clinical activities of his Department and Division, is a co-editor of Nelson Textbook of Pediatrics and of Pediatric Infectious Diseases: Principles and Practice, and authors the book Pocket Guide to Vaccination and Prophylaxis.
Charles T. Leach, M.D.
Dr. Leach received his medical degree at the University of Utah School of Medicine and completed his pediatrics residency as well as a fellowship in pediatric infectious diseases at UCLA.
He is currently Associate Professor and Director of Research in the Department of Pediatrics at the University of Texas Health Science Center at San Antonio.
Dr. Leach conducts scientific research in the areas of herpes virus infections, pediatric AIDS, and infectious diseases among residents of the Texas-Mexico border.
Copyright 2012 Hal B. Jenson, M.D., All Rights Reserved