Fifth disease, also known as erythema infectiosum (air-uh-THEE-muh infekshe-O-sum), is a common viral infection of infants and young children that causes a characteristic slapped-cheek rash.
Most people with fifth disease have mild symptoms and do not become seriously ill; some may not have any symptoms at all. However, the disease can be serious for people with certain blood disorders, such as sickle cell anemia * , because parvovirus B19 can temporarily cause or worsen existing anemia * . For most people, temporary anemia is not a problem, but for those who already have anemia, the condition can become severe, causing paleness, fatigue, and a fast pulse. People with weakened immune systems, such as those who have AIDS * or cancer or who have had an organ transplant, can also develop severe anemia as a result of fifth disease.
Parvoviruses can infect animals, but these are not the same strains * that affect humans. Therefore, a person cannot catch fifth disease from a dog or cat, and a pet cannot catch it from an infected person.
Fifth disease occurs most commonly in children between the ages of 5 and 15 years, but adults can also get it. It often occurs in outbreaks (e.g., among classmates at school or children in a child-care center) in the winter and spring, but people can get it throughout the year.
Fifth disease spreads quickly. At home, up to half of family members exposed to someone with fifth disease become infected. If an outbreak occurs in school, up to 60 percent of students may get the virus.
A person with fifth disease can spread the infection in the early part of the illness, before the rash develops. By the time the rash appears (about a week after being exposed to the virus), a person most likely is no longer contagious. Once someone is infected with parvovirus B19, that person develops immunity * to it and will usually not become infected again.
Parvovirus B19 passes from one person to another through nose and mouth fluids, such as mucus and saliva. Any direct contact with the fluids of an infected person, whether through a cough, sneeze, or by sharing drinking glasses or utensils, can spread the infection.
Fifth disease can also be passed from pregnant women to their unborn babies. Most of the time, the baby is not harmed. Occasionally, the infection can cause severe anemia in the baby and lead to miscarriage * , especially if the baby was infected in the first half of pregnancy.
In children, doctors can usually diagnose fifth disease simply by looking for the telltale rash on the face and body. In cases in which there is no rash, blood tests can confirm the presence of parvovirus B19.
Most people with fifth disease do not require treatment. Antibiotics do not help because the illness is caused by a virus rather than bacteria. Symptoms such as fever or joint pain may be treated with acetaminophen * .
The rash clears up on its own, often within one to three weeks. Joint pain and swelling can take longer to go away, sometimes up to several months. People with joint pain may need to rest and restrict their activities until they feel better.
People with blood disorders or immune deficiencies who develop severe anemia as a result of fifth disease may require a blood transfusion * and other specialized medical care.
The vast majority of people who are infected with parvovirus B19 recover completely without any complications. Severe anemia, the complication most often associated with fifth disease, usually affects people with weakened immune systems or blood disorders and, rarely, unborn babies who were infected during the first half of pregnancy.
In healthy people, parvovirus B19 infection can sometimes affect the ability of the bone marrow (the soft tissue inside bones where blood cells are made) to make new red blood cells, but this effect is usually temporary and does not cause significant anemia or other problems.
There is no vaccine to prevent fifth disease. The best way to prevent the spread of infection is to practice good hygiene, including frequent hand washing and not sharing drinking glasses or eating utensils. Because the disease is most contagious before the telltale rash appears, it is difficult to keep the infection from spreading among family members or young children in school or day care. By the time the rash appears and the illness is diagnosed, the person is usually no longer contagious.
See also Anemia, Bleeding, and Clotting • German Measles (Rubella) • Scarlet Fever
Livingston, Michael, and Kate MacKeracher. “Erythema Infectiosum, Fifth Disease, and Parvovirus P19: How Did They Get Together in the First Place?” University of Western Ontario Medical Journal 78, 2 (2013): 23–28. Available online at http://www.uwomj.com/wpcontent/uploads/2013/06/v78n2.23-28.pdf (accessed November 7, 2015).
MedlinePlus. “Fifth Disease.” National Library of Medicine, U.S. National Library of Medicine. http://www.nlm.nih.gov/medlineplus/fifthdisease.html (accessed November 7, 2015).
Organization of Teratology Information Specialists. “Fifth Disease (parvovirus B19) and Pregnancy.” Organization of Teratology Information Specialists, February 2014. http://www.mothertobaby.org/files/Fifth_Disease.pdf (accessed June 11, 2016).
Centers for Disease Control and Prevention. 1600 Clifton Rd., Atlanta, GA 30333. Toll-free: 800-311-3435. Website: http://www.cdc.gov (accessed November 7, 2015).
March of Dimes. 1275 Mamaroneck Ave., White Plains, NY 10605. Telephone: 914-997-4488. Website: http://www.marchofdimes.org (accessed November 7, 2015).
* sickle cell anemia is a hereditary condition in which the red blood cells, which are usually round, take on an abnormal crescent shape and have a decreased ability to carry oxygen throughout the body.
* anemia (uh-NEE-me-uh) is a blood condition in which there is a decreased hemoglobin in the blood and, usually, fewer than normal numbers of red blood cells.
* AIDS, or acquired immunodeficiency (ih-myoo-no-dih-FIH-shensee) syndrome, is an infection that severely weakens the immune system. It is caused by the human immunodeficiency virus (HIV).
* strains are various subtypes of organisms, such as viruses or bacteria.
* immunity (ih-MYOON-uh-tee) is the condition of being protected against an infectious disease.
* miscarriage (MIS-kare-ij) is the end of a pregnancy through the death of the embryo or fetus before birth.
* acetaminophen (uh-see-tehMIH-noh-fen) is a medication commonly used to reduce fever and relieve pain.
* blood transfusion is the process of giving blood (or certain cells or chemicals found in the blood) to a person who needs it due to illness or blood loss.