Fifth Disease (Erythema Infectiosum)

Fifth Disease

If it weren’t for fifth disease, I would never have become a coauthor of a lead article in The New England Journal of Medicine.

While investigating the outbreak of this infection among some of our nursing staff in 1988, I learned that the illness is caused by parvovirus B19 and is a common, mild childhood illness. It got the name fifth disease in 1899 because it was the fifth of six common childhood illnesses found that caused a rash.

The virus was discovaered in 1975 by scientists in England; however, they still didn’t know what diseases it caused. In 1981, the connection was made between parvovirus B19 and aplastic crisis, a serious condition that affects people with sickle-cell disease when they are exposed to the virus. Finally, in 1983, scientists figured out that the same virus caused fifth disease.

How Do You Get It?

Fifth disease spreads through mouth and nose secretions in much the same way that a cold spreads. One infected family member can spread it to the family at any one time. It may also spread from contact with objects contaminated with the virus and can possibly travel short distances through the air in small droplets. The virus is also present in the blood of infected people, so it can be caught through a blood transfusion. A British report found two cases spread through tattooing.

Outbreaks occur from late winter through spring among school-age children and teenagers, about 10 to 60 percent of whom will catch fifth disease. The outbreaks, which vary in extent from year to year, stop once school is out.

About 60 percent of adults acquired antibodies because of childhood infection and so are immune. Nonimmune adults are susceptible. In the outbreak in my hospital, only nursing staff members who had close personal contact with the patients became infected. Doctors who merely spent a brief time in the patients’ rooms were not infected.

How Do You Know If You Have It?

Children may have a headache, mild fever, and slight tiredness or muscle pains when they are coming down with fifth disease. After two to three days they will break out in a flushed reddish rash on both cheeks, called “slapped cheek” appearance, which lasts about three days. By the time the cheek rash appears, the child feels better. This smooth red rash often becomes lacy and usually spreads to the trunk, upper arms, and thighs. About half the time the rash is itchy in children as well as adults.
The most common symptoms for adults are fever and joint pains, especially in the knees. Adults do not have the slapped cheek rash, but do have the lacy rash which is also easy to recognize. It looks blotchy and spreads from the trunk to arms and legs.

Other common symptoms are headache, muscle aches, loss of appetite, tiredness, and swollen lymph glands behind the neck.

People with sickle-cell disease do not get fifth disease, but rather have a more serious infection from parvovirus B19 called aplastic crisis, meaning that their bone marrow stops making red blood cells. They suffer from high fever, weakness, and severe pain. These patients require hospitalization and blood transfusions.

Tests

Tests are not necessary or available to diagnose fifth disease. But if you are pregnant or in a high risk group, it is possible to test for immunity to parvovirus so if you are exposed you’ll know if you’re at risk of infection. These antibody tests are available through state health departments, the CDC, and some private labs.

Aplastic crisis is confirmed by a blood test called a reticulocyte count. Reticulo-cytes are early forms of red blood cells. If this count is zero, you are in aplastic crisis. As you recover from the crisis, the count goes way up, then back down to normal, which is 0.5 to 2.

How Sick Will You Be?

In healthy children, fifth disease is mild. Children may feel ill for the few days before the rash appears. After that, they are not contagious and usually feel well enough to attend school.

Some of the nurses who got fifth disease were very ill and had to cancel vacation plans. Others had such a mild illness they didn’t even miss work. In adults, the recurring joint pains are the most serious symptom. Some of the nurses could barely walk during the worst few days. The joint pains mimic arthritis—it’s worse in the morning, and worse in wet weather.

Most babies born to women infected during pregnancy are normal and healthy. Because the virus is able to cross the placenta and infect the fetal tissues, however, pregnant women are at risk. How much risk? We don’t know. Studies have estimated that at most 2.5 percent of pregnant women infected with parvovirus have spontaneous abortions or stillbirths. If you are pregnant and work in a setting with young children during a fifth disease outbreak you should discuss the situation with your obstetrician. If blood tests confirm active parvovirus B19 infection your doctor may consider doing serial ultrasound exams for several weeks to monitor for any fetal problems.

Incubation Period

The incubation period is generally between 4 and 16 days.

Infectiousness

Children with fifth disease are infectious for only one to three days before the rash appears. Sickle-cell patients in aplastic crisis are infectious for a longer time. They can spread parvovirus B19 through their respiratory secretions and urine for about seven to ten days.

Immunity

Infection gives immunity, and 60 percent of adults are immune.

Complications

The disease can cause chronic anemic conditions for anyone who has sickle-cell disease or any abnormality in red blood cells, who is undergoing immunosuppressive treatment for cancer, who is an organ recipient, or who has HIV infection. People in these high risk groups must seek a doctor’s care if exposed to fifth disease.

How Do You Treat It?

There is no treatment for fifth disease. Red blood cells are given to sickle-cell patients until they have gotten over the aplastic crisis and can make their own red blood cells. Cancer patients may have to discontinue chemotherapy until the anemia improves. Some doctors have tried giving antibodies from donor blood to pregnant women and people with weakened immune systems to help them get over the infection.

Nursing Care

Because most children are barely sick, they don’t require much nursing care. You can give acetaminophen for fevers higher than 101°F (38.3°C) or to relieve aching muscles. If your child suffers from an itchy rash, spread calamine lotion over the itchy areas.

Adults can take aspirin or ibuprofen to relieve the joint pains. When you first start to feel ill and tired, bed rest is a good idea. Later, if you have recurring joint pains swimming is the best exercise to relieve stiff and swollen joints.

How Do You Prevent It?

No prevention exists. If your children are healthy, however, you don’t need to worry about preventing fifth disease. Even those in high-risk groups can’t really do much about preventing infections caught in a household or school. In hospitals, anyone in the infectious stage of parvovirus B19 will be isolated from other patients.