Dear Doctor Theriot,
Last week my first grader had a rash and was diagnosed as having Fifth Disease. I was told by her doctor that she could continue to go to school. Now two of her classmates have the same illness. I feel somewhat responsible. Should I have kept her out of school?
Let me put your mind at ease by saying that you did the right thing in letting your daughter continue school. To better understand why this is so, let me explain a little about Fifth Disease, or "Erythema Infectiosum" (EI). EI is a viral illness caused by Human Parvovirus B-19. In most cases it causes a mild self-limiting and self-resolving illness (i.e. gets better without treatment). Around 15-30 percent of affected individuals develop fever. A smaller number may develop sore or swollen joints, but the hallmark of EI is a particular rash which occurs in stages. The rash typically starts on the face with an intense redness of the cheeks giving the appearance of a paleness around the mouth, a "slapped face appearance". After 1-2 days this facial rash fades to be followed by a racy or reticular measles-like rash on the arms and shoulders which then spreads to the trunk and buttocks. This rash may last for weeks and often times will come and go, becoming more intense and florid in direct sunlight or heat (a hot bath, etc). Aside from this obvious rash, the individual is otherwise usually fine.
Man is the only known host of EI and the virus is spread by secretions from the respiratory tract (coughing and sneezing) and from blood. Studies have documented that persons with EI are most contagious before the onset of the illness such that by the time the rash occurs they are no longer contagious. The incubation period is 4-14 days. Outbreaks do occur in the spring months usually in elementary schools. There are three cases in which EI may pose a more serious problem--these are in patients with immunodeficiency, chronic hemolytic anemias (Sickle-cell disease eg.), and pregnant women where there seems to be an increased risk of fetal death. These, however, are beyond the scope of this article.
I hope this gives a clearer picture of Fifth Disease which is an interesting and peculiar virus. The rest assured, letting your daughter go to school while she had the Fifth Disease rash was in no way a mistake on your part.