Erythema (air-uh-THEE-ma) infectiosum (in-fek-tee-OH-sum), also called Fifth disease, is an infection that mostly occurs in children.
Erythema infectiosum (EI) is a childhood exanthem occurring with primary parvovirus B19 infection, characterized by edematous erythematous plaques on the cheeks (“slapped cheeks”) and an erythematous lacy eruption on the trunk and extremities.
Causes of Erythema Infectiosum
Viremia develops 6 days after intranasal inoculation of B19 into volunteers who lack serum antibodies to the virus. Nonspecific symptoms occur during this time. IgM and then IgG antibodies develop after a week and clear viremia. Significant bone marrow depression can occur at this time. The exanthem begins 17 to 18 days after inoculation and may be accompanied by arthralgia and/or arthritis; these findings are mediated by immune complexes. In compromised hosts, B19 can destroy erythroid precursor cells, causing severe aplastic crisis in adults and hydrops fetalis in the fetus.
Symptoms of Erythema Infectiosum
The first sign of the infection is a rash on the face that looks like the child has been slapped. After 1 or 2 days, the rash spreads to other parts of the body.
The child may also have flu or cold symptoms such as a low fever, headache, runny nose, pain in the joints, sore throat, and cough. Some children get an upset stomach or may throw up. The rash may get brighter and itch after the child has been out in the sun and following exercise or a warm bath.
Diagnosis
Blood tests can be used to confirm the diagnosis but are rarely necessary.
Treatment
No treatment is usually required for fifth disease in children. If fever or joint discomfort is present then oral acetaminophen (such as Tylenol) may be given.
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