What Is Fifth Disease?
Fifth disease, or erythema infectiosum, is a contagious viral infection common among school-age children. It’s most common during late winter, spring, and early summer. About 50% of adults are immune to fifth disease because they had it in childhood, often without knowing it. There is no vaccine for it.
Fifth disease got its name many years ago when it was the fifth on a list of the six recognized childhood rash-forming illnesses. The others are rubella, measles, scarlet fever, chickenpox, and roseola infantum.
Fifth Disease Symptoms
In children, symptoms of fifth disease often start out like a cold. Then, within 7 to 10 days, a rash usually develops. Common symptoms of fifth disease include:
- Mild fever
- Stuffy or runny nose
- Bright red cheeks
- A flat or raised red rash, usually on the arms and legs, which lasts from 2 to 39 days and may itch; the rash fades from the center of the red areas toward the edges, giving it a lacy appearance. The rash can recur with exercise, warm baths, rubbing the skin, or emotional upset.
The most recognized sign of fifth disease is the red rash across the cheeks that looks as if the child has been slapped. You might also hear it called slapped-cheek disease. But not all children with fifth disease get the rash.
It’s less common, but some kids also have:
- Sore throat
- Joint pain
- Swollen glands
- Red eyes
- Rash that looks like bruises or blisters
The disease is rare in infants and adults. Adults usually don’t get a rash, but they do tend to get more serious flu-like symptoms, including:
- Sore throat
- Muscle pain
- Joint pain, particularly in the hands, wrists, knees, and ankles
- Belly pain
Fifth Disease Causes
Fifth disease is caused by parvovirus B19. This parvovirus only infects humans. Other forms of the virus can infect dogs and cats.
Fifth Disease Transmission
Fifth disease is spread through blood and by respiratory droplets that enter the air when an infected person coughs or sneezes. Adults who work with young children – such as child care providers, teachers, and health care workers – are most likely to be exposed.
By the time the rash appears, children are no longer contagious and may attend school or day care. The incubation period (the time between infection and signs or symptoms of illness) is usually 4-14 days, but it can be as long as 21 days.
Fifth Disease Prevention
To limit the spread of fifth disease among children at home or in a child care setting, take the following steps:
- Wash hands often, especially after wiping or blowing noses and before preparing or eating food.
- Don't share food, pacifiers, bottles, eating utensils, or drinking cups.
- If toys tend to end up in tots' mouths, clean and disinfect them often.
- Don't kiss children on the mouth.
- Play outdoors as much as possible. It's easier for the virus to spread indoors where people are likely to be in closer contact.
- Make sure kids are not crowded together, especially during nap time.
- Teach children to cough or sneeze into a tissue (which should be thrown out right away) or the inside of their elbow (which is less likely than their hands to spread the virus) and away from other people.
- Children with fifth disease generally don't need to be excluded from day care, as they're unlikely to be contagious after the rash appears and a diagnosis has been made.
Pregnancy and fifth disease
If you don't have immunity to fifth disease and are pregnant, take steps to avoid infection. For instance, if there's an outbreak of fifth disease in your workplace, discuss with your doctor whether to stay home from work until it subsides. At home, wash your hands thoroughly after touching tissues used by infected children and dispose of these tissues promptly. Avoid sharing drinking glasses or utensils with anyone who has the illness or was exposed to it.
Some doctors recommend giving immunoglobulin if you're pregnant and have been exposed to the virus.
Fifth Disease Diagnosis
In most cases, fifth disease is diagnosed based on the appearance of typical symptoms.
A blood test can confirm whether you have fifth disease, but this usually is not necessary if you have a healthy immune system.
If you're pregnant and you've been exposed to fifth disease, you may be given a blood test to determine whether you had it in the past and are, therefore, immune.
If you get fifth disease while you're pregnant, either an amniocentesis or a test called percutaneous umbilical blood sampling (PUBS) can be used to test for the virus in your baby and find out how severe fetal anemia is, if it exists. Fifth disease can affect how your body or your baby's body makes red blood cells and cause severe anemia, although this is rare.
Ultrasound can look for complications in your unborn baby, such as abnormal pooling of fluid around the heart, lungs, or belly. But most of the time, fifth disease doesn't cause your baby any problems.
Fifth Disease Treatment
The goal of fifth disease treatment is to ease symptoms and make you or your child more comfortable. There’s no specific medicine to treat the virus that causes fifth disease. Your doctor might suggest:
- Acetaminophen to help lower fever
- Ibuprofen for joint or muscle pain
- Antihistamines to treat itching that may come with the rash
If you have sickle cell anemia, chronic anemia, or an impaired immune system, you can get a shot of immunoglobulin to fight off the virus. You may also need transfusions of red blood cells.
Fifth Disease Complications
Fifth disease is usually mild for otherwise healthy kids and adults and poses little risk to health.
But it can cause chronic anemia in some people. You could need a blood transfusion, which would require a hospital stay.
You’re more likely to have serious complications from fifth disease if you have a weakened immune system. Conditions that can weaken your immune system include leukemia and other cancers, HIV infection, and organ transplants.
If you’re pregnant and think you may have the virus, call your doctor. Babies in utero don’t usually get the virus if their mother has it, and it hasn’t been shown to cause birth defects.
But if a fetus does become infected, the virus can make it less able to produce red blood cells, leading to a dangerous form of anemia, heart failure, and sometimes miscarriage or stillbirth. A woman who gets the virus while pregnant has about a 2% chance of miscarriage.
When to Call Your Doctor About Fifth Disease
You should make that call to your doctor when:
- Your child has sickle cell anemia, any other chronic anemia or an impaired immune system and has been exposed to fifth disease or is showing symptoms.
- You're pregnant, you don't know whether you're immune to parvovirus B19 (or know that you are not immune), and you come into contact with anyone who has an infection with parvovirus B19.
- The rash becomes purple, painful, blistered, or lasts longer than 5 weeks.
- Your infected child looks or acts very ill.