What is Erythema Infectiosum?

Erythema infectiosum is a common illness of childhood, caused by a virus called human parvovirus B19 (PV-B19). Worldwide, infection with this virus is most common in late winter and early spring. The annual incidence rate of infection is cyclical, with higher rates of infection occurring every four to seven years. The disease is minor in children, but may cause serious health problems in adults, people with deficient immune systems, pregnant women, and people with anemia. Erythema infectiosum is also known as fifth disease and slapped cheek syndrome.

Childhood infection with human parvovirus B19 (PV-B19) is largely harmless. The main symptom is an itchy rash which spreads over the entire body, and is heaviest on the cheeks, arms, and legs. In teenagers and adults, stiff, painful, swollen joints are a common additional symptom. Activities which involve bending the joints tend to be painful and difficult. Other symptoms of erythema infectiosum in adults or children may include headache, fatigue, fever, nausea, and diarrhea.

While most symptoms of erythema infectiosum are mild and harmless, the disease may cause serious symptoms in some people. Women in their first trimester of pregnancy are at risk of spontaneous abortion if they are infected with the virus. The infection can cause a potentially fatal condition called hydrops fetalis, in which fluid builds up in the chest cavity of the developing fetus. The fetus is also at risk of anemia and congestive heart failure.

People with chronic hemolytic anemia disorders such as sickle-cell disease are also at risk of serious complications. Chronic hemolytic anemia disorders are the result of abnormal levels of red blood cell destruction. In the event of an infection with human parvovirus B19 (PV-B19), people with hemolytic anemia may enter into an aplastic crisis situation, in which large numbers of immature red blood cells are destroyed. Someone in an aplastic crisis is at risk of dangerously low blood oxygen levels, which may be fatal if not treated promptly. Aplastic crisis can typically be averted with a blood transfusion.

Anyone with an immune deficiency is at risk of potentially serious complications. The greatest risk is of a chronic viral infection which may affect red and white blood cell production in the bone marrow. In the case of a compromised immune system, treatment with antiviral medication is necessary to prevent a serious infection.

In most people, the viral infection causes only minor symptoms; therefore, erythema infectiosum treatment is usually limited to pain management with over-the-counter medications such as ibuprofen. Plenty of fluids and rest are also recommended, and antihistamine medications may be used to alleviate skin itching.