Roseola is a generally mild viral illness that usually affects babies and young children. The condition typically causes several days of fever, followed by a rash.

Two common strains of the herpes virus cause roseola. It usually affects children between 6 months and 3 years of age, though it occasionally affects adults.

Some children develop only a very mild case of roseola and never show any clear indication of illness, while others experience the full range of signs and symptoms. The infection can occur at any time of the year.

It begins with a sudden high temperature up to 40ºC. The temperature lasts for about three days.

In some cases febrile fits follow the high temperature. These may seem very dramatic and alarming. Febrile fits are not caused by the three-day-fever as such, but are due to the sudden high rise in temperature.

The rash appears when the temperature suddenly drops again after about three days. It usually begins on the body and spreads to the arms and legs. It is seldom seen in the face.

The rash consists of pale, reddish spots, perhaps with small heads. It lasts for about 12 to14 hours. Then it is over:

Older infants are at greatest risk of acquiring roseola because they haven't had time yet to develop antibodies against many viruses. While in the uterus, babies receive antibodies from their mothers that protect them as newborns from contracting infections such as roseola. But that immunity fades with time.

The most common age for a child to contract roseola is between 6 and 12 months.