Erythema Infectiosum
Erythema infectiosum (fifth disease) is a contagious viral infection that causes a blotchy or raised red rash with mild illness.
Erythema infectiosum is caused by human parvovirus B19 and occurs most often during the spring months, often in geographically limited outbreaks among children and adolescents. Infection is spread mainly by breathing in small droplets that have been breathed out by an infected person. The infection can also be transmitted from mother to fetus during pregnancy; it rarely causes stillbirth or severe anemia and excess fluid and swelling (edema) in the fetus (hydrops).
Symptoms begin about 4 to 14 days after infection. Symptoms can vary, and some children have none. However, a child with erythema infectiosum typically has a low fever, feels mildly ill, and develops red cheeks that often look like they have been slapped. Within a day or two, a rash appears, especially on the arms, legs, and trunk but not usually on the palms or soles. The rash can be itchy and consists of raised, blotchy red areas and lacy patterns, particularly on areas of the arms not covered by clothing, because the rash may be worsened by exposure to sunlight.
The illness generally lasts 5 to 10 days. Over the next several weeks, the rash may temporarily reappear in response to sunlight, exercise, heat, fever, or emotional stress. In adolescents, mild joint pain and swelling may remain or come and go for weeks to months.
Erythema infectiosum can also present in a different way, particularly in children with sickle cell disease, or immunodeficiency diseases, such as acquired immunodeficiency syndrome (AIDS). The virus can affect the bone marrow and produce severe anemia.
A doctor makes the diagnosis based on the characteristic appearance of the rash. Blood tests can help identify the virus, although these are rarely performed. Treatment is aimed at relieving the fever and pain.
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