What Is Fifth Disease?
Fifth disease, also called erythema infectiosum, is a viral infection that is most common in children. It is named fifth disease because it is fifth on the list of childhood viral rash diseases — roseola, measles, rubella, chicken pox and fifth disease. The human parvovirus B19, which causes fifth disease, is not the same parvovirus common to animals. The disease is spread through contact with airborne droplets from the throat and nose of infected people. Adults who are not immune can become infected with the virus. According to the Mayo Clinic, about 50 percent of adults are immune to the disease.
A child will typically have a rash, known as a "slapped-cheek" rash, headache, sore throat, nausea, low fever and itching. Adults may have no obvious symptoms. If symptoms are present, it is usually flu-like symptoms and joint pain or swelling that lasts for days or weeks. If joints are affected, the most frequent locations are the ankles, knees, wrists and hands. The Arthritis Foundation reports that as many as 10 percent of adults experiencing joint pain from fifth disease may develop chronic symptoms. A parvovirus B19 infection is contagious for about a week before symptoms, such as the rash, appear.
The diagnosis of this condition is usually made by the characteristic rash and other symptoms common to the disease. Diagnosing fifth disease in adults may require a blood test to look for parvovirus antibodies, which are proteins produced by the immune system in people who have had or been exposed to parvovirus B19.
According to Lab Tests Online, there are two types of antibodies associated with parvovirus B19 — IgM and IgG. IgM antibodies indicate a recent exposure to the virus. IgG antibodies show up a few weeks after the initial infection. By determining the blood level of either or both the IgM and IgG antibodies, your doctor can determine if fifth disease is active, recent or occurred sometime in the past.
Treatment and Complications
Treating fifth disease consists of managing the symptoms, such as pain, fever or itching. Rest and limiting activities may be necessary for adults with the disease to recover from the joint pain and swelling. Possible complications include severe anemia, which may require blood transfusions in people with impaired immune systems, and pregnancy complications, which can cause a miscarriage or stillbirth.
Since fifth disease is contagious before symptoms begin, it is impossible to avoid contact with the virus. General precautionary measures are recommended at all times, such as frequent hand washing. Once infected, you are immune to the virus for life.
Mayo Clinic: Parvovirus Infection https://www.mayoclinic.com/health/parvovirus-infection/DS00437/DSECTION=tests-and-diagnosis
Arthritis Foundation: Fifth Disease – What Is It? https://www.arthritis.org/disease-center.php?disease_id=11&df=definition
Lab Tests Online: Parvovirus B19 https://www.labtestsonline.org/understanding/analytes/parvo/test.html