Roseola, sometimes called Sixth Disease or baby measles, is characterized by a high fever, followed by a pink-red raised or flat rash lasting anywhere from 1-3 days.
This viral infection appears most often in between six months and two of age.
It is possible to have the virus without having noticeable symptoms. But roseola usually starts out with a sudden, relatively high fever, often above 103 degrees Fahrenheit.
The fever typically lasts three to five days and may end abruptly, followed by the telltale rash. The rash may last for days or only hours.
The rash is pink and may have small flat spots or raised bumps. These spots may have a lighter "halo" around them and may turn white if you press on them.
The rash isn't itchy or uncomfortable, and contact with the rash itself doesn't spread the illness. It's usually seen on the trunk and neck, but it can extend to the arms, legs, and face.
If your baby has roseola, he may also be irritable and tired and have mild diarrhea, a decreased appetite, and swollen eyelids. The lymph nodes in his neck and at the base of his skull may also be a bit enlarged. In general, children with roseola don't appear especially ill, considering how high their fevers get.
About 10 to 15 percent of children with roseola have a febrile seizure. If this happens, your baby may become unconscious and jerk his arms, legs, or facial muscles for two or three minutes. He may also lose control of his bladder or bowels.
Although frightening, fever-induced seizures in young children are seldom serious and rarely harmful. If you can, try to time the length of the seizure. Your baby's doctor will want to know how long the episode lasted.
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https://www.empowher.com/condition/roseola/definition