Mrs. K. brought her six-year-old daughter Emma to the office to get her “cleared” to return to class. “I need a note from you to get her back into school,” she said in a frustrated voice. “Emma has had this rash for almost a week, and they won’t let her back into class until it is gone. She has been perfectly fine and I’m afraid she is falling behind,” she pleaded.
Sure enough, Emma did not have a fever, and she looked fine to me. When she took off her shirt to show me the rash, I asked her mom how recently Emma’s cheeks had been red and flushed. She thought for a minute, and then asked, “How did you know her cheeks were red?” She had a perplexed look on her face and went on. “It was around five or six days ago that Emma DID have red cheeks...and since her skin is so fair, it was quite noticeable. My husband and I thought that she possibly had sunburn or a windburn, but we couldn’t explain it because she hadn’t really spent much time outdoors...and then two days later it went away. Then she got this rash on her body.”
As it turned out, Emma’s facial rash occurred during the weekend, and by the time she reported to school on Monday, she had the rash on her arms. This prompted the school to call Mrs. K. to come pick Emma up. She was told to keep Emma at home until the rash went away. Finally, by the fifth day of this, she brought Emma to the office.
I assured Mrs. K. that Emma could go to class directly from my office because she has fifth disease and was in no way contagious. I immediately wrote a note to that effect. Fifth disease is a viral illness that is caused by Human Parvovirus B-19 that only affects humans. It is a self-limiting and benign disease that is also known as Erythema Infectiosum (EI). It received the name “fifth disease” because in the early 1900’s it was the fifth disease described in a scheme of childhood illnesses that caused rashes. The others were rubella, measles, scarlet fever and atypical scarlet fever. It was then named Erythema Infectiosum. The Human Parvovirus was identified and associated with human disease in 1981.
EI is spread through the respiratory tract; the incubation period ranges from 3 - 28 days with an average of around two weeks. EI is a seasonal virus for the most part, with peak prevalence in late winter and spring. It is primarily a childhood illness with 70% of cases during an outbreak occurring in children 5 - 15 years of age. Many studies have shown that 60-70% of the adults tested have antibodies against the virus, which proves the adults had previous infection, and thus, lifelong immunity against EI.
EI is a benign illness in general. Only 15 - 30% of affected individuals with EI will develop a fever, which tends to be low-grade. The first real sign of EI is a red rash of the cheeks that is often described as a “slapped-face” appearance. It has also been described that a patient with fifth disease has a pallor around the mouth. This is really due to the fact that the cheeks are so flushed. The facial rash lasts one-to-two days and then fades, giving way to a “lacy” or reticular rash on the trunk. This rash then spreads down the extremities and is more pronounced on the extensor surfaces of the extremities. The palms and soles are always spared. The rash tends to wax and wane for up to a couple of weeks. It can become more florid with heat (running or playing hard, sunlight exposure, taking a hot bath or shower, etc.).
A small percentage of affected individuals with EI will have a headache, joint stiffness and pain (usually the hands, knees and ankles), and swollen lymph nodes. This is more common in adults.
There are certain groups of individuals who are at a higher risk when they become infected with Human Parvovirus B-19. The first of this group are people who have chronic hemolytic conditions such as sickle-cell-disease, thalassemia and hereditary spherocytosis. When they get EI, it may cause the bone marrow to shut down causing a drop in the red blood cell production (aplastic crisis), which is a serious problem. The next group of concern are in pregnant women. It has been shown that there MAY be an increased incidence of spontaneous abortions in women who become infected with EI during the second trimester of pregnancy, but the reported number is less than 5%. The final group at risk for EI are individuals who have compromised immune systems. These individuals are at risk for developing chronic anemia or chronic infections. It must be stressed that these cases are rare.
An interesting study about EI sheds light on the contagiousness of the virus. The authors looked at family members of affected individuals. When a child came down with EI, they did daily viral cultures on family members for Parvovirus B-19. What they found was that the members who subsequently came down with EI actually shed the virus for the days leading up to the first appearance of the facial rash. Once the rash appeared, they no longer shed the virus and, as a result, were NOT contagious to others and should be allowed to attend class. That is also why there are outbreaks in schools and daycare centers. By the time that EI is discovered, the die is cast!
Mrs. K. was pleased to hear this and looked at Emma saying, “Honey, isn’t that good news? You can go back to school today!” Emma was less enthusiastic and flashed me a most disappointed look. Clearly her mind was racing, and then her eyes lit up. “Doctor?” she asked very seriously. “I think the nurse should take my temperature again. I think I now have a fever.” It was a nice try.