Fifth Disease: An Update

US Pharm. 2019;44(4):28-30.

Fifth disease (erythema infectiosum), a mild skin-rash disorder that is caused by human parvovirus B19, is more common in children than in adults. Fifth disease originally acquired its common name when it appeared fifth on a listing of six recognized childhood rash-forming illnesses (the other disorders on that list were measles, scarlet fever, rubella, chickenpox, and roseola infantum). This mildly-to-moderately contagious viral infection usually manifests within 4 to 14 days of exposure and is common among school-aged children, particularly in the winter and spring.^1,2

Although it resembles other childhood rashes, such as rubella or scarlet fever, fifth disease usually begins with the distinctive, sudden appearance of bright red cheeks that look as though they have been slapped (hence the informal name “slapped cheek disease”). Fifth disease is less common in babies and adults.²

Viral Exanthem

A viral exanthem is a skin rash or eruption that appears when a patient’s body is fighting off a virus. Some rashes are specific to the kind of virus that is causing them. Often, it is never determined exactly which virus caused the rash, and some rashes may signal a serious illness. This type of rash can be more serious if the patient is pregnant. A viral exanthem may be caused by many kinds of viruses, such as measles, chickenpox, roseola infantum, rubella, fifth disease, and others. Because of the exanthem, the skin may be dry, bumps and blisters may appear on the skin, and the skin may be sore to the touch. An exanthem may also be caused by toxins, drugs, or other microorganisms or by autoimmune disease.³

Signs and Symptoms

The early symptoms of fifth disease are usually mild and may include fever, runny nose, headache, sore throat, itching, cough, and muscle ache. These initial symptoms last 2 to 5 days, after which the rash—the most recognized feature of fifth disease—appears on the face. After a few days, the rash moves to the chest, arms, buttocks, and legs and shows a unique pattern. The rash varies in intensity and typically disappears in 7 to 10 days, but it can come and go for several weeks.⁴

Patients may also develop joint pain and swelling, known as polyarthropathy syndrome. This phenomenon is more common in adults, especially women. Some adults with fifth disease have painful joints—usually in the hands, feet, or knees—and no other symptoms. The joint pain usually lasts 1 to 3 weeks but may last for months or longer. It usually goes away without any long-term problems.^3,4

Causes and Disease Course

Fifth disease is caused by human parvovirus B19 and is spread by respiratory droplets and secretions, such as saliva, sputum, or nasal mucus, when an infected person sneezes or coughs. By the time the rash appears, the child is no longer contagious and may attend school or day care. The incubation period is usually 4 to 14 days but may last as long as 21 days. In a pregnant patient, infection in the first half of pregnancy may carry a small risk of severe anemia in the fetus, as well as a 10% risk of miscarriage.^5,6

Fifth disease is usually mild in children and adults who are otherwise healthy. In some people, however, fifth disease can lead to serious health complications, such as chronic anemia requiring medical treatment. People who have sickle cell disease or a weakened immune system caused by leukemia or other cancer, an organ transplant, or HIV infection may be at risk for serious complications from fifth disease.^7,8 About 20% of people who contract the virus are asymptomatic, but they can still pass it to others.

Patients are most contagious when they have just fever or cold symptoms (i.e., before the rash or joint pain and swelling develop). After the rash manifests, contagion is unlikely, so at that point it is safe for the patient to go back to school or work. Fifth disease patients with a weakened immune system may be contagious for a longer period of time, however. Parvovirus B19 can spread through the blood, which is why a pregnant patient infected with it can pass it to her fetus; the virus can also be spread through blood products.⁹

Once a patient recovers from fifth disease, he or she develops immunity that generally is protective against parvovirus B19 infection in the future.⁹

Diagnosis

A physician usually is able to diagnose fifth disease by observing the typical rash during an office visit. If joint symptoms have outlasted the rash or if the rash never developed, a blood test may be performed to detect antibodies to the virus. This is not a routine test, but it may be performed in special cases. The blood test may be particularly helpful for pregnant patients who may have been exposed to parvovirus B19 and are suspected of having fifth disease. It is important to remember that a serologic diagnosis is possible only for a short time because the level of antibodies specific to a recent parvovirus B19 infection is elevated for just 2 months following the initial infection.¹⁰

Prevention

There is no vaccine or medication that can prevent human parvovirus B19 infection. People can reduce their chance of being infected or infecting others by washing their hands often with soap and water, covering their mouth and nose when they cough or sneeze, not touching their eyes, nose, or mouth, avoiding close contact with people who are sick, and staying home when they are sick.^2,10

As mentioned above, once the rash develops, the patient is probably not contagious. Therefore, it is usually safe for the child to return to school or a childcare center. All healthcare providers and patients should follow strict infection-control practices to prevent parvovirus B19 from spreading.⁴

Treatment

Fifth disease typically is mild and goes away on its own. Children and adults who are otherwise healthy usually recover completely. Treatment generally involves relieving symptoms, such as fever, itching, and joint pain and swelling.¹¹ Patients who have complications from fifth disease should see their healthcare provider for medical treatment.¹¹

The fever and joint pain of fifth disease in children may need no treatment or can be alleviated with acetaminophen or ibuprofen (no aspirin, however). Adults who have joint pain and swelling may need to rest, alter their activities, and take nonsteroidal anti-inflammatory drugs, such as aspirin, ibuprofen, or naproxen sodium. In severe cases, antiviral drugs may be administered. Patients with chronic parvovirus arthritis occasionally may benefit from drugs such as hydroxychloroquine and corticosteroids, but this is rarely necessary. Increased fluid intake to prevent dehydration and cool baths with baking soda or Aveeno to relieve itching have been recommended.¹¹

Parvovirus B19 causes infection only in humans. Cat and dog parvoviruses do not infect humans. Although no vaccine is available for human parvovirus B19, attempts have been made to develop one.¹¹

CDC Recommendation

Fifth disease usually is mild and disappears on its own, and children and adults whose overall health is good typically will recover completely. The CDC recommends that one of the best ways to take care of one’s health is to practice self-management. Consuming a balanced diet, drinking an adequate amount of fluids, and getting sufficient rest are paramount in the successful management of fifth disease by caregivers and patients.

REFERENCES

1. Servant-Delmas A, Morinet F. Update of the human parvovirus B19 biology. Transfus Clin Biol. 2016;23(1):5-12.
2. Metry D, Katta R. New and emerging pediatric infections. Dermatol Clin. 2003;21(2):269-276.
3. Young NS, Brown KE. Parvovirus B19. N Engl J Med. 2004;350(6):586-597.
4. CDC. Fifth disease. www.cdc.gov/parvovirusb19/fifth-disease.html. Accessed March 15, 2019.
5. Admani S, Jinna S, Friedlander SF, Sloan B. Cutaneous infectious diseases: kids are not just little people. Clin Dermatol. 2015;33(6):657-671.
6. CDC. Pregnancy and fifth disease. www.cdc.gov/parvovirusb19/pregnancy.html. Accessed March 15, 2019.
7. Smith-Whitley K, Zhao H, Hodinka RL, et al. Epidemiology of human parvovirus B19 in children with sickle cell disease. Blood. 2004;103(2):422-427.
8. Zikidou P, Grapsa A, Bezirgiannidou Z, et al. Parvovirus B19-triggered acute hemolytic anemia and thrombocytopenia in a child with Evans syndrome. Mediterr J Hematol Infect Dis. 2018;10(1):e2018018.
9. Katta R. Parvovirus B19: a review. Dermatol Clin. 2002;20(2):333-342.
10. Ogunsile FJ, Currie KL, Rodeghier M, et al. History of parvovirus B19 infection is associated with silent cerebral infarcts. Pediatr Blood Cancer. 2018;65(1):Epub August 17, 2017.
11. Clinical Drug Information. Lexi-Comp Online. Hudson, OH: Lexi-Comp, Inc; 2017. www.wolterskluwercdi.com/lexicomp-online. Accessed March 15, 2019.

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