What is roseola?

Quick Answer
A disease characterized by a mild fever and a rash that mostly affects young children.
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Causes and Symptoms

Roseola is caused by the human herpesvirus 6, to which most children have been exposed by age four. Immunity passed from mother to fetus usually protects infants from contracting roseola before they are six months old. Although the precise period of time during which patients are contagious is unknown, health professionals have determined that the virus incubates for as many as ten days after exposure. Patients usually are contagious only during the fever phase of roseola.

A child with roseola develops a fever that can reach 106 degrees Fahrenheit and persist for two to five days. The lymph glands in the throat may become swollen, and upper respiratory congestion may occur. Some children appear agitated, while others do not behave in an ill manner and continue normal activities. Lethargy, lack of appetite, and diarrhea may accompany the fever. The fever occasionally causes febrile seizures as the brain reacts to sudden and extreme temperature changes. Approximately 5 to 15 percent of roseola patients experience these convulsions, which last several minutes and usually are not harmful.

When the fever ceases, a red or pink rash appears on most patients’ bodies and remains for several hours to three days. When pressed, the rash blanches. It does not blister, cause pain, or itch. Occasionally, a roseola patient is feverish and never develops a rash or has a rash without a preceding fever. A rash may appear prematurely during the fever phase or be delayed until after the fever has subsided. Some children infected with roseola never display any symptoms. Rarely, roseola can precede encephalitis and aseptic meningitis.

Treatment and Therapy

Treatment for roseola consists of methods to soothe symptoms. Pediatricians recommend baths and the use of acetaminophen and ibuprofen, if the child is old enough, to lower the fever. Health professionals also advise patients to drink fluids to prevent dehydration. The patient should be isolated until the fever is gone.

A child who has convulsions should be examined by medical professionals immediately. Patients with dark purple rashes should also be seen by physicians, as should children whose rashes do not blanch when touched or remain more than several days. Blisters and itchy or painful rashes also demand professional attention. Children with roseola who seem unusually sick should also be taken for examination, as should children with prolonged fevers that do not improve with medication and baths.

Most patients recover fully. Although the resulting antibodies are present in most adults, roseola can be reactivated if the immune system is weakened.

Perspective and Prospects

Roseola has been referred to in medical literature since the mid-nineteenth century. Early twentieth century investigators unsuccessfully attempted to identify the disease’s pathogen. By 1988, medical professionals determined that the herpevirus 6 causes roseola. Two strains, A and B, have been identified, with strain B causing most roseola cases in children. The herpesvirus 7 has been linked to cases occurring in older patients.


Gershon, Anne A., Samuel L. Katz, and Peter J. Hotez, eds. Krugman’s Infectious Diseases of Children. 11th ed. Philadelphia: Mosby, 2004.

Grossman, Leigh B., ed. Infection Control in the Child Care Center and Preschool. 8th ed. Charlottesville, Va.: Silverchair Science, 2012.

Hoekelman, Robert A., ed. Primary Pediatric Care. 4th ed. St. Louis, Mo.: Mosby, 2001.

Parker, James N., and Phillip M. Parker. Roseola: A Medical Dictionary, Bibliography, and Annotated Research Guide to Internet References. San Diego, Calif.: Icon Health, 2004.

"Roseola." Health Library, November 26, 2012.

"Roseola." MedlinePlus, August 2, 2011.