Roseola - 小愛微恙，愛娘殫精積慮

Exanthem subitum (meaning sudden rash), also referred to as roseola infantum (or rose rash of infants), sixth disease (as the sixth rash-causing childhood disease) and (confusingly) baby measles, or three day fever, is a benign disease of children, generally under two years old, whose manifestations are usually limited to a transient rash ("exanthem") that occurs following a fever of about three day's duration.

Until recently, its origin was unknown, but it is now known to be caused by two human herpesviruses, HHV-6 (Human Herpesvirus Six) and HHV-7, also called Roseolovirus.

Clinical features of exanthem subitum

Typically the disease affects a child between six months and three years of age, and begins with a sudden high fever of 102-104 degrees Fahrenheit (39-40 degrees Celsius). This can cause, in some cases, febrile convulsions (also known as febrile seizures or "fever fits") due to the sudden rise in body temperature, but in many cases the child appears and acts normal. After a few days the fever subsides, and just as the child appears to be recovering, a red rash appears. This usually begins on the trunk, spreading to the limbs but usually not affecting the face. It disappears again in a matter of hours to a day or so. In contrast, a child suffering from measles would usually appear more infirm, with symptoms of conjunctivitis and a cough, and their rash would affect the face and last for several days. Liver dysfunction can occur in rare cases, and the rare adult who contracts the disease can show signs of mononucleosis.

 Vaccines and treatment

There is no specific vaccine against or treatment for exanthem subitum, and most children with the disease are not seriously ill. A child with fever should be given plenty of fluids to drink, and paracetamol/acetaminophen or ibuprofen to reduce their temperature (but never aspirin, due to the risk of Reye's Syndrome^[1]). He or she should also be kept more lightly clothed than normal if he or she is very hot. The rash is not particularly itchy and needs no special lotions or creams.

It is likely that many children acquire exanthem subitum "subclinically"; in other words, they show no outward sign of the disease. Others may be debilitated enough that a doctor's opinion is required to confirm the diagnosis, and particularly to rule out other more serious infections, such as meningitis or measles. In case of febrile seizures, medical advice is essential.

From Wiki:  http://en.wikipedia.org/wiki/Roseola