Fifth disease, also known as erythema infectiosum or “slapped cheek syndrome,” is a common viral illness caused by parvovirus B19. This virus infects only humans and is one of the five classic childhood rash illnesses, along with measles, scarlet fever, rubella, and roseola. The infection is found worldwide and often appears during late winter and spring. It mainly affects school-aged children between 5 and 15 years old, though adults can also get it. In adults, symptoms may differ and can include joint pain instead of the typical rash.
The disease is best known for its distinctive rash. It usually starts with bright red cheeks, giving a “slapped cheek” appearance, followed by a light pink, lace-like rash that spreads to the body, arms, and legs. The rash may fade and return over several weeks, especially after exposure to sunlight, heat, exercise, or stress.
Parvovirus B19 spreads through droplets from the mouth or nose when an infected person coughs, sneezes, or talks. It can also be transmitted through blood or from a pregnant person to their baby. The time between infection and symptoms, known as the incubation period, is typically 4 to 14 days. People are most contagious before the rash appears, when symptoms resemble a mild cold, making it difficult to identify and prevent early spread.
Before the rash develops, symptoms may include mild fever, tiredness, headache, sore throat, or a runny or stuffy nose. These early symptoms usually disappear once the rash appears. In most healthy people, fifth disease is mild and goes away on its own without medical treatment.
While the illness is generally harmless, it can cause problems for some individuals. Pregnant people who contract the virus, especially early in pregnancy, may pass it to the fetus, which can lead to severe anemia, fluid buildup (known as hydrops fetalis), or, in rare cases, miscarriage. People with weak immune systems or chronic blood disorders, such as sickle cell disease or thalassemia, are also at risk of developing severe or long-lasting anemia.
There is no specific medicine or vaccine for parvovirus B19. Treatment focuses on managing symptoms with rest, fluids, and over-the-counter pain or fever relief, such as acetaminophen or ibuprofen. People with anemia or weakened immune systems may need medical care and monitoring.
Good hygiene practices can help prevent the spread of the virus. These include frequent handwashing, covering the mouth and nose when coughing or sneezing, cleaning commonly touched surfaces, and staying home when sick. Because people can spread the virus before showing symptoms, total prevention is difficult, but good hygiene remains the best defense.
Origin of the Name
The term “Fifth Disease” originates from its place in a historical list of five common childhood rash illnesses, also known as exanthems. During the early 20th century, physicians categorized these diseases numerically based on their clinical features and frequency of occurrence. The list included: (1) measles (rubeola), (2) scarlet fever, (3) rubella (German measles), (4) Dukes’ disease (a condition later thought to overlap with scarlet fever or staphylococcal infections), and (5) erythema infectiosum, now known as fifth disease.
The name does not reflect the severity, order of discovery, or frequency of the illness but simply denotes its position in this classification system. The condition was formally described in medical literature in 1905 by French physician Cheinisse, who recognized its distinctive rash pattern as separate from other known exanthems. With the identification of parvovirus B19 in 1975 as the causative agent, fifth disease became one of the first childhood rash illnesses definitively linked to a specific virus. The label remains a traditional way to categorize the illness among other similar childhood diseases.
Key Characteristics
Fifth disease is most easily recognized by its characteristic facial rash, which gives the appearance of having been “slapped” on both cheeks. This vivid red facial rash is often followed by a lighter, lace-like rash that spreads to the arms, trunk, thighs, and buttocks. The rash may cause mild itching and can fluctuate in intensity over several weeks, fading and reappearing with exposure to sunlight, warm temperatures, physical activity, or emotional stress.
The illness typically follows three stages. In the first stage, the infected person may experience mild, flu-like symptoms such as low fever, headache, fatigue, or sore throat. During this phase, the individual is most contagious. In the second stage, the characteristic facial rash appears, signaling the end of contagiousness. The third stage involves the spread of the lacy rash across the body, which may last for one to three weeks.
In adults, particularly women, fifth disease can present differently. Instead of the classic rash, adults often experience joint pain or swelling, especially in the hands, wrists, knees, and ankles. These symptoms, known as arthropathy, are temporary but can persist for several weeks or, rarely, months.
The illness usually resolves within one to three weeks without the need for medical treatment. For diagnostic confirmation, laboratory tests can detect parvovirus B19-specific antibodies or viral DNA in the blood. The presence of IgM antibodies indicates a recent infection, while IgG antibodies suggest past exposure and immunity.
Causes and Transmission
Fifth disease is caused by parvovirus B19, a small, single-stranded DNA virus belonging to the Parvoviridae family. It is the only parvovirus known to infect humans and is distinct from animal parvoviruses, which do not cause disease in people.
Parvovirus B19 Infection
Parvovirus B19 primarily targets red blood cell precursors—immature cells in the bone marrow responsible for producing red blood cells. The virus binds to a receptor known as the P antigen, found on the surface of these cells, allowing it to enter and replicate within them. In healthy individuals, this temporary interruption in red blood cell production usually goes unnoticed because the body quickly replaces the lost cells. However, in people with conditions that already reduce red blood cell counts, such as sickle cell disease, thalassemia, or other hemolytic anemias, parvovirus B19 infection can cause a sudden and severe drop in red blood cells, leading to what is known as a transient aplastic crisis.
The infection can present in several ways depending on age and health status. In children, it commonly causes the classic “slapped cheek” rash and mild flu-like symptoms. Adults, particularly women, may experience joint pain and swelling especially in the hands, wrists, knees, and ankles, sometimes without any visible rash. People with weakened immune systems, such as those undergoing chemotherapy, living with HIV/AIDS, or taking immunosuppressive drugs, may experience prolonged or chronic infection, as their immune system is less able to clear the virus.
Once infected, individuals typically develop lasting immunity due to the production of protective antibodies, making reinfection rare.
Modes of Transmission
Parvovirus B19 spreads mainly through respiratory droplets, which are tiny particles released when an infected person coughs, sneezes, talks, or breathes in close proximity to others. These droplets can be inhaled or transferred through contact with contaminated surfaces followed by touching the mouth, nose, or eyes. The virus is resilient and can survive on surfaces for short periods, although transmission through inanimate objects (fomites) is considered uncommon.
Less frequently, the virus can be transmitted through blood and blood products, particularly during transfusions or organ transplants, as well as from a pregnant person to their fetus. In pregnancy, the virus can cross the placenta and infect the developing baby’s red blood cell precursors, potentially leading to severe fetal anemia or, in rare cases, fetal death. However, such outcomes are uncommon and typically occur only when infection happens during the first half of pregnancy.
Studies show that outbreaks often occur in schools, daycare centers, and households, where close contact facilitates the spread of respiratory droplets. The virus is also more common in late winter and spring, though it can occur year-round in any climate.
Contagious Period
A key feature of parvovirus B19 infection is that individuals are most contagious before symptoms appear, particularly before the rash develops. During this early stage, known as the prodromal phase, a person may experience mild symptoms such as low fever, fatigue, runny nose, or general malaise. This phase usually lasts 5 to 10 days, during which the virus is actively present in respiratory secretions and easily transmissible to others.
Once the rash appears, the viral load in the blood and respiratory tract drops sharply, and the individual is no longer considered contagious. This timing has important implications for public health: by the time the characteristic rash is visible, the person has typically already stopped spreading the virus. Therefore, isolation after the rash appears is generally unnecessary.
In school or childcare settings, recognizing this pattern helps reduce unnecessary exclusion of children who are no longer infectious. Standard hygiene measures such as proper handwashing, covering coughs and sneezes, and cleaning shared surfaces remain the most effective strategies for preventing transmission in both community and household environments.
Symptoms and Stages
Fifth Disease progresses through distinct phases marked by specific symptoms. These include early signs of mild illness, a characteristic rash, and differences in symptom expression between children and adults.
Initial Signs
Initial Signs (Prodromal Phase)
The prodromal phase of fifth disease typically occurs 4 to 14 days after exposure to parvovirus B19. During this period, the virus multiplies in the respiratory tract and bloodstream before the appearance of the rash. Symptoms are often mild and may go unnoticed, particularly in children.
Early manifestations commonly include:
- Low-grade fever (usually below 38.5°C or 101°F)
- Headache or general malaise
- Sore throat and nasal congestion resembling a mild cold
- Fatigue or body aches
- Decreased appetite or mild gastrointestinal discomfort
In adults and older children, transient arthralgia (joint pain) or myalgia (muscle pain) may appear at this stage, though it is more pronounced later in the illness. This early phase lasts about 2 to 5 days and corresponds to the period when the infected individual is most contagious. Once the rash appears, the risk of transmission significantly diminishes.
Rash Development
The hallmark feature of fifth disease is its two-stage rash progression. The first manifestation is the “slapped cheek” rash, a bright red flush that appears suddenly on both cheeks, often sparing the area around the mouth and nose. This erythematous facial rash gives the child a characteristic look and is a result of immune-mediated vascular changes triggered by the viral infection.
Within one to four days, the facial rash is followed by a secondary lacy or reticular rash that spreads to the trunk, arms, thighs, and buttocks. This pattern consists of pale pink or reddish patches with a lace-like, netted appearance. The rash may vary in intensity and distribution, fading and reappearing for several weeks, especially in response to heat, sunlight, stress, or exercise.
In some cases, mild itching (pruritus) accompanies the rash, particularly on the body. Despite its alarming appearance, the rash is painless, non-vesicular (does not form blisters), and typically resolves within 7 to 10 days without scarring or pigmentation changes.
Progression in Children Versus Adults
The expression of fifth disease differs notably between children and adults.
In Children:
Most children experience mild illness, and the facial and body rash are the most distinctive signs. Fever, sore throat, and malaise may precede the rash but usually resolve quickly. Children seldom experience complications, and recovery occurs within 1 to 3 weeks. The rash may reappear intermittently for up to a month, especially with temperature changes or emotional stress.
In Adults:
Adults infected with parvovirus B19 are less likely to develop the classic rash and more prone to arthropathy (joint pain or swelling). These symptoms commonly affect the small joints of the hands, wrists, knees, and ankles and are more frequent in women. The pain may resemble rheumatoid arthritis but usually resolves within days to weeks. In rare cases, however, chronic or relapsing joint pain may persist for several months. Adults may also experience fatigue, mild fever, and malaise, with or without a noticeable rash.
After the rash fades, individuals typically feel well again, though mild tiredness or residual joint discomfort may persist. In healthy individuals, full recovery occurs without lasting effects. However, in people with weakened immune systems or chronic hemolytic anemias (such as sickle cell disease or hereditary spherocytosis), the virus can temporarily halt red blood cell production, leading to transient aplastic crisis, a potentially serious complication.
The immune response generated during infection provides lifelong immunity, meaning reinfection is exceedingly rare. This natural protection explains why fifth disease primarily affects children and is uncommon in adults who were previously exposed.
Diagnosis of Fifth Disease
Fifth Disease is identified primarily through characteristic symptoms and confirmed with specific tests when necessary. Diagnosis involves careful clinical assessment supported by laboratory analysis to differentiate it from similar conditions.
Clinical Evaluation
The initial and most crucial step in diagnosing fifth disease is clinical examination, which focuses on the visual recognition of the distinctive rash and accompanying symptoms. Physicians often identify the illness based on the presence of the “slapped cheek” rash, a bright red eruption that appears suddenly on both cheeks and spares the area around the mouth and eyes. This striking facial rash is followed, within a few days, by a lacy or reticular rash spreading over the trunk, arms, and legs. The progression and fading pattern of the rash, along with the absence of severe systemic symptoms, help distinguish fifth disease from other viral exanthems.
In addition to the rash, doctors assess prodromal symptoms such as low-grade fever, malaise, headache, or mild respiratory discomfort that typically precede the eruption. Joint pain and swelling, when present—especially in adults—provide additional diagnostic clues. A detailed medical history is also essential, particularly inquiries about recent contact with someone who had similar symptoms, school or daycare exposure, or occupational risk factors (e.g., teachers or healthcare workers who interact frequently with children).
Because fifth disease can mimic other illnesses, clinical evaluation includes differential diagnosis. The goal is to rule out other rash-causing diseases such as:
- Rubella (German measles) – typically presents with lymph node swelling and a rash that begins on the face but spreads downward.
- Measles (rubeola) – accompanied by high fever, cough, and Koplik spots inside the mouth before rash onset.
- Scarlet fever – caused by group A Streptococcus and associated with a sandpaper-like rash and strawberry tongue.
- Drug eruptions or allergic rashes – usually accompanied by itching and lack of systemic viral symptoms.
Timing plays a vital role in clinical differentiation. Unlike many other exanthems, fifth disease’s rash usually appears after the contagious phase has ended, a key feature that helps guide isolation and public health decisions.
Laboratory Testing
Although clinical features alone are often sufficient for diagnosis, laboratory tests are valuable in confirming parvovirus B19 infection, especially in cases with atypical presentations or where complications are suspected.
The primary diagnostic tests include:
- Serologic Testing (Antibody Detection): Blood tests measuring parvovirus B19-specific antibodies—IgM and IgG—are the most commonly used method. IgM antibodies appear about 10 to 12 days after infection and indicate recent or active infection. IgG antibodies develop several days later and indicate past infection or immunity. A positive IgM and negative IgG suggest an ongoing infection, whereas the presence of both indicates recovery and long-term immunity.
- Polymerase Chain Reaction (PCR): PCR testing detects the viral DNA of parvovirus B19 directly in blood or other body fluids. It is highly sensitive and useful for detecting infection in individuals who cannot mount a normal antibody response such as those with compromised immune systems, HIV infection, or patients undergoing chemotherapy. PCR is also used in pregnant women when serologic results are ambiguous, as it helps confirm maternal infection and guide fetal monitoring.
- Complete Blood Count (CBC) and Reticulocyte Count: In some cases, doctors may order these tests to evaluate red blood cell production, especially in patients with anemia or hemolytic disorders. Parvovirus B19 temporarily halts the production of red blood cells in the bone marrow, which can lead to transient aplastic crisis in susceptible individuals. A sharp drop in reticulocyte count (immature red cells) can signal this complication.
Treatment and Management
For the majority of healthy children and adults, treatment is supportive, aiming to alleviate symptoms while the immune system clears the infection. Because fifth disease is mild in most cases, hospitalization is rarely required. Patients are encouraged to rest adequately, stay well-hydrated, and maintain a balanced diet to support recovery. During the acute phase, particularly when fever or malaise is present, minimizing physical activity can help the body recover more efficiently.
There is no role for antibiotics, as the illness is viral in origin. Likewise, antiviral medications have not been shown to be effective against parvovirus B19. Instead, symptom management and patient education form the cornerstone of care.
Home Care Recommendations
Home management is the primary treatment approach for fifth disease. The following measures can help reduce symptoms and promote comfort:
- Adequate rest allows the immune system to focus on clearing the virus. Drinking plenty of fluids such as water, fruit juices, or broths helps prevent dehydration, particularly when fever is present.
- Over-the-counter medications like acetaminophen (paracetamol) or ibuprofen can be used to manage fever, headache, and joint discomfort. Aspirin should be avoided in children due to the risk of Reye’s syndrome, a rare but serious condition.
- The rash associated with fifth disease may cause mild itching or warmth. Applying cool compresses or calamine lotion can soothe irritation. Loose, breathable clothing may also help prevent further skin irritation.
- Scratching the rash can break the skin and lead to secondary bacterial infections. Keeping nails trimmed and using mild antihistamines for itching (if prescribed by a doctor) can reduce this risk.
- Although individuals are most contagious before the rash appears, maintaining good hand hygiene is still important to limit spread. Patients should stay home if they have fever, fatigue, or respiratory symptoms. Once the rash develops, they are usually no longer contagious and may return to school or work if they feel well.
Parents and caregivers should monitor children for signs of prolonged fatigue, worsening rash, or unusual symptoms, and seek medical advice if these occur.
Medical Interventions
While most people recover without medical assistance, certain situations require professional evaluation and treatment:
- In adults, particularly women, joint pain (arthralgia) and swelling (arthritis) can last for several weeks or even months. When symptoms are significant, nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naproxen may be recommended for relief. In rare, prolonged cases, referral to a rheumatologist may be necessary to rule out autoimmune conditions like rheumatoid arthritis, which can mimic parvovirus-induced joint inflammation.
- Individuals with chronic hemolytic disorders such as sickle cell disease, thalassemia, or hereditary spherocytosis are at risk for transient aplastic crisis. This condition occurs when parvovirus B19 temporarily halts red blood cell production, leading to severe anemia. Treatment may involve hospitalization, blood transfusions, and supportive care until the bone marrow resumes normal function. In these patients, early recognition of symptoms like pallor, fatigue, or rapid heartbeat is essential.
- People with weakened immune systems (e.g., due to HIV infection, chemotherapy, or organ transplantation) may be unable to clear the virus effectively, leading to chronic infection. These patients can develop persistent anemia and prolonged viral shedding. Management may include intravenous immunoglobulin (IVIG) therapy, which provides antibodies that help neutralize the virus and restore red blood cell production.
- Parvovirus B19 infection during pregnancy requires special attention. If a pregnant woman tests positive or has been exposed to the virus, her healthcare provider may perform serologic testing to assess for recent infection. When infection is confirmed, ultrasound monitoring is used to detect fetal anemia or hydrops fetalis (a severe buildup of fluid in the fetus). In rare cases of severe fetal anemia, intrauterine blood transfusions may be performed to improve fetal outcomes. Although most pregnancies proceed without complications, careful follow-up is vital for early detection and intervention.
- If the rash persists beyond several weeks, appears atypical, or is accompanied by other systemic symptoms such as shortness of breath or joint swelling, additional investigations may be necessary to exclude other underlying diseases or coinfections.
Complications and Risks
Fifth Disease is usually mild, but it can cause specific complications in certain groups. These risks depend largely on the individual’s health status and life stage.
Risks for Pregnant Women
Pregnant women represent one of the most vulnerable groups affected by parvovirus B19 infection. The virus can cross the placenta and infect the developing fetus, primarily targeting red blood cell precursors. This interference with fetal erythropoiesis can lead to severe anemia and, in some cases, hydrops fetalis—a life-threatening condition marked by excessive fluid accumulation in fetal tissues and organs.
The risk of adverse outcomes is greatest during the first half of pregnancy, especially before 20 weeks’ gestation. Infection later in pregnancy is generally less harmful but still requires close observation. The estimated rate of fetal loss following maternal infection ranges between 2% and 10%, depending on gestational age and maternal immune response.
If a pregnant woman is diagnosed with parvovirus B19 infection, serial ultrasound examinations are recommended to assess fetal well-being. These ultrasounds monitor for signs of fetal anemia, such as cardiomegaly (enlarged heart), ascites, or skin edema. In cases where fetal anemia or hydrops is detected, intrauterine blood transfusion may be performed to restore red blood cell levels and improve survival chances.
Pregnant women who have been exposed to a confirmed case of Fifth Disease should seek prompt medical evaluation. Serological testing (IgG and IgM) can determine immunity or recent infection. Women found to be non-immune should be closely monitored throughout pregnancy for potential complications.
Risks for Individuals with Blood Disorders
Patients with chronic hemolytic conditions, such as sickle cell disease, thalassemia, or hereditary spherocytosis, face a unique complication known as aplastic crisis. This occurs when parvovirus B19 temporarily halts red blood cell production in the bone marrow. Because these individuals already experience accelerated red cell destruction, even a brief cessation in production can lead to severe, life-threatening anemia.
Symptoms of an aplastic crisis include extreme fatigue, pallor, rapid heartbeat, and shortness of breath. Hospitalization and blood transfusions are often required until the bone marrow resumes normal red cell production. Prompt medical attention can prevent serious outcomes, and patients with known hemoglobinopathies are encouraged to seek evaluation immediately if exposed to the virus or experiencing sudden anemia.
Possible Long-Term Effects
Fifth Disease typically resolves without lasting effects in healthy individuals. However, some patients may develop chronic joint pain, particularly adults. This arthritis-like symptom can affect the hands, wrists, knees, and ankles.
The joint pain usually lasts a few weeks but can persist for months in rare cases. Immunocompromised individuals are at greater risk for prolonged or severe symptoms, including chronic anemia.
No evidence suggests permanent organ damage from the infection. Long-term follow-up is advised for those with persistent symptoms or underlying health issues.
Prevention Strategies
At the individual level, preventing fifth disease relies on consistent personal hygiene and responsible behavior when illness is suspected. Since parvovirus B19 spreads primarily through respiratory secretions, minimizing droplet transmission is key to preventing infection.
- Regular and thorough handwashing with soap and water remains the most effective preventive measure. Hands should be washed for at least 20 seconds, especially after coughing, sneezing, nose blowing, or touching the face. When soap and water are unavailable, alcohol-based hand sanitizers can be used as an alternative.
- Individuals should cover coughs and sneezes with a tissue or the inner elbow instead of their hands. Used tissues should be discarded immediately, followed by handwashing. This reduces droplet spread on hands and surrounding surfaces.
- The virus can survive for short periods on surfaces, so regular cleaning and disinfection of frequently touched items such as doorknobs, toys, light switches, and countertops helps limit indirect transmission. Disinfectants containing bleach or alcohol are effective against the virus.
- During the contagious phase (before the rash appears), individuals experiencing fever, fatigue, or cold-like symptoms should limit close contact with others, particularly pregnant women or those with weakened immune systems. This includes avoiding shared utensils, drinks, and personal items.
- Children showing symptoms of fifth disease or early viral signs should be kept home until they feel well enough to return. However, because the virus is often transmitted before symptoms are recognized, isolation after rash onset may have limited impact. Still, keeping visibly ill children at home helps prevent the spread of other coexisting respiratory infections.
- In settings with known outbreaks such as schools, clinics, or crowded public spaces, wearing protective masks can help reduce droplet spread. Masks are particularly recommended.