Fifth disease is a common and highly contagious childhood illness caused by parvovirus B19. It gets its name from being fifth on a historical list of childhood rashes. For most children, it is mild and clears up on its own. However, it can cause serious complications in pregnant women, people with certain types of anaemia, and those with weakened immune systems. As always, speak with your family doctor if you have concerns about your symptoms or your child’s health.
What Is Fifth Disease?
Fifth disease is sometimes called “slapped cheek disease” because of the bright red rash that appears on the face. This rash is one of its most recognizable signs. The illness is caused by parvovirus B19, a virus that only infects humans. It is completely different from the parvovirus that affects dogs and cats, so you cannot catch it from a pet.
The infection is most common among elementary school-aged children. Outbreaks tend to happen during winter and spring. However, anyone can get fifth disease at any time of year. About half of all adults are already immune, likely because they had a mild or unnoticed infection as a child.
For more background on parvovirus B19, visit Health Canada’s official health information resource.
How Does Fifth Disease Spread?
Fifth disease spreads from person to person in ways similar to the common cold. The virus travels through respiratory droplets from coughing, sneezing, and saliva. Close contact and hand-to-hand contact can also pass the virus along. In addition, it can spread through blood, and an infected pregnant woman can pass it to her unborn baby.
When Is It Contagious?
This is an important point that surprises many parents. A person with fifth disease is most contagious before the rash appears — typically during the week before the rash shows up. Once the rash develops, the person is generally no longer considered contagious. Therefore, children with the rash do not usually need to be kept home from school or daycare.
Recognising the Symptoms of Fifth Disease
The early symptoms of fifth disease are easy to mistake for a mild cold or flu. Knowing what to look for can help you identify it sooner. Symptoms tend to appear in stages.
Early Stage Symptoms
In the first few days, you or your child may notice:
Low-grade fever
Runny nose
Headache
Mild fatigue
These early symptoms can last about a week. Many people never connect them to fifth disease at this stage.
The Rash Stage
After the early symptoms fade, the signature rash appears. It starts as a bright red flush on both cheeks — hence the “slapped cheek” nickname. A few days later, a lacy, pinkish-red rash may spread to the trunk, arms, and legs. The rash can come and go for several weeks, especially with heat, exercise, or stress.
Joint Pain in Adults
Adults with fifth disease often experience joint pain and swelling, particularly in the hands, wrists, and knees. This can be uncomfortable and may last weeks or even months. However, it typically goes away on its own without permanent damage. Rest and over-the-counter anti-inflammatory medications can help ease the discomfort.
Fifth Disease in Pregnancy: What You Need to Know
Fifth disease in pregnancy requires special attention. For most healthy adults, the illness is mild. However, if a pregnant woman contracts parvovirus B19, it can have serious consequences for her unborn baby. The virus can cross the placenta and infect the fetus.
Risks to the Unborn Baby
Research shows the following risks when a pregnant woman is infected with fifth disease:
Approximately 30% of fetuses will contract the virus from an infected mother.
About 10% of infected pregnancies may result in miscarriage.
Around 3% of infected fetuses may develop fetal anaemia, known as hydrops fetalis.
When hydrops fetalis is treated with intrauterine blood transfusions, 60–80% of fetuses survive.
The good news is that early diagnosis and prompt treatment can significantly reduce these risks. Fetal ultrasound is often recommended around 8 to 10 weeks after the initial infection to check for any abnormalities. Blood tests can confirm whether infection has occurred.
If you are pregnant and think you may have been exposed to fifth disease, contact your family doctor or midwife right away. Do not wait for your next scheduled appointment. For further reading, see this overview from the Mayo Clinic on parvovirus infection.
Fifth Disease, Anaemia, and Weakened Immune Systems
For most people, parvovirus B19 causes only mild illness. However, for certain groups, the infection can become serious. Understanding your risk is important.
People With Anaemia
Anaemia is a condition where the body does not have enough healthy red blood cells to carry oxygen throughout the body. Parvovirus B19 can temporarily stop the production of red blood cells. For someone who already has anaemia, this can trigger a serious crisis.
People with sickle cell anaemia face a particularly high risk. Fifth disease can cause what is known as an aplastic crisis — a sudden and severe drop in red blood cell production. This may require hospitalisation and blood transfusions.
People With Weakened Immune Systems
Fifth disease can also cause severe anaemia in people whose immune systems are not functioning properly. This includes people living with:
HIV infection
Cancer and undergoing chemotherapy
Organ transplant recipients taking anti-rejection medications
In these cases, the body may struggle to clear the virus, leading to ongoing or worsening anaemia. Specialised treatment, including antibody therapy, may be needed. These patients should be monitored closely by their healthcare team.
Diagnosis and Treatment of Fifth Disease
In many cases, a doctor can diagnose fifth disease by looking at the rash and reviewing symptoms. However, blood tests can confirm recent infection or check for immunity. This is especially helpful for pregnant women or people at higher risk of complications.
Treatment Options
For otherwise healthy children and adults, there is no specific antiviral treatment for fifth disease. Treatment focuses on managing symptoms. This may include:
Rest and plenty of fluids
Over-the-counter fever reducers such as acetaminophen (like Tylenol) or ibuprofen (like Advil)
Anti-inflammatory medications for joint pain in adults
More serious cases — such as in people with anaemia or weakened immune systems — may require hospitalisation and blood transfusions. Pregnant women with confirmed infection will need close monitoring by their obstetric team. In some cases, intrauterine blood transfusions may be recommended for the fetus.
How to Help Prevent Fifth Disease
There is currently no vaccine for fifth disease in Canada. However, you can reduce the risk of spreading or catching the virus with some simple steps:
Wash your hands often with soap and water, especially after blowing your nose or coughing.
Use disposable tissues and throw them away immediately after use.
Avoid close contact with people who are sick.
Do not share cups, utensils, or personal items.
These habits are especially important in schools, daycares, and shared workplaces. For a broader look at hand hygiene and infection prevention, see this resource from the World Health Organization on hand hygiene.
When to See a Doctor
Most cases of fifth disease do not require a doctor’s visit. However, there are situations where you should seek medical advice promptly. Visit your family doctor or a walk-in clinic if:
You are pregnant and have been exposed to fifth disease or develop a rash.
Your child has a known blood disorder such as sickle cell anaemia.
You or your child has a weakened immune system due to illness or medication.
Symptoms are severe, worsening, or not improving after a week or two.
Joint pain is persistent or significantly affecting daily life.
Your child develops an unusual or widespread rash you cannot identify.
In Canada, your provincial health plan covers doctor visits for concerns like these. If you do not have a family doctor, a walk-in clinic is a convenient and accessible option. Do not hesitate to seek care — catching complications early makes a real difference.
Frequently Asked Questions About Fifth Disease
Is fifth disease dangerous for children?
For most healthy children, fifth disease is mild and resolves on its own within a few weeks. Serious complications are rare in children with healthy immune systems. However, children with sickle cell anaemia or other blood disorders need to be seen by a doctor promptly.
Can adults get fifth disease?
Yes, adults can get fifth disease, though about half of all adults are already immune from a childhood infection. Adults who do get it often experience more noticeable joint pain and swelling than children do. The rash may also be less prominent in adults.
How long does fifth disease last?
The early cold-like symptoms of fifth disease typically last about a week. The rash can come and go for up to several weeks, often triggered by heat, sunlight, or physical activity. Joint pain in adults may last from weeks to a few months in some cases.
Can you get fifth disease more than once?
Most people who have had fifth disease develop lifelong immunity and do not get it again. A simple blood test can check whether you are immune. This is particularly useful information for pregnant women who want to know their risk level.
Should my child stay home from school if they have fifth disease?
Once the rash of fifth disease appears, your child is generally no longer contagious. Most children can return to school at that point if they feel well enough. Check with your child’s school and your family doctor if you are unsure, especially during a known outbreak.
Is there a vaccine for fifth disease in Canada?
Currently, there is no approved vaccine for fifth disease in Canada. Prevention relies on good hygiene practices such as frequent handwashing and avoiding contact with infected individuals. Research into a parvovirus B19 vaccine has been ongoing, but none is yet available for public use.
Key Takeaways
Fifth disease is a common, mild childhood illness caused by parvovirus B19 — not the same parvovirus that affects pets.
It spreads like a cold through respiratory droplets and close contact, and is most contagious before the rash appears.
Most healthy children and adults recover fully without treatment beyond rest and symptom relief.
Pregnant women, people with anaemia, and those with weakened immune systems face a higher risk of serious complications and should seek medical advice promptly.
About 30% of fetuses exposed during pregnancy may contract the virus; early monitoring and treatment can greatly improve outcomes.
There is no vaccine for fifth disease in Canada. Regular handwashing and good hygiene are the best prevention tools.
If you are concerned about yourself or your child, visit your family doctor or a local walk-in clinic. Your provincial health plan covers these visits.
