Roseola infantum
Sudden rash (roseola infantum or exanthema subitum) is one of the frequent rash-causing diseases of infancy and early childhood that is caused by a virus.
How is it caused?
It is caused by types of herpes viruses (type 6 and type 7). The human body is exposed to these viruses for the first time during infancy and early childhood. Most newborns are protected by special antibodies, which have passed into their blood from their mother via the placenta. After 6 months of life this protection is weakened.
Which ages does it affect?
The typical ages of sudden rash appearance are the ages between 6 and 18 months.
During which season do the incidents occur?
Incidents of sudden rash in infants occur throughout the year.
What is the incubation period?
From the time that an infant comes into contact with a person carrying the virus until the time that symptoms occur, usually around 10 days pass.
How is it transmitted?
The virus is transmitted by droplets of saliva from other infants with the disease, or more often, from older people who have milder, or no symptoms, but carry the virus.
What is the clinical image of sudden rash?
Sudden rash often has a characteristic clinical image and course:
There is usually a short first period, during which the infant has mild symptoms from the upper respiratory system for a few days, with a slight runny nose, mild eye redness, and mild coughing.
Then the baby gets a high fever, which can reach 40 degrees. Despite being high, the fever drops relatively easily with antipyretics, and the child, despite the high fever, is in a relatively good mood. Fever typically lasts for about 3 days, and finally subsides abruptly.
12 to 24 hours after the end of the fever, the rash appears. The rash appears suddenly, it consists of red spots on the torso, and it usually spreads to the neck, the face, and the arms. There are no blisters or papules, and the child usually doesn't feel itchy. The rash subsides gradually and disappears, typically during the next 3 days.
There are cases when this viral infection leads to fever without the subsequent rash.
What complications may occur?
The most frequent and most significant complication is febrile seizures. 5 to 10% of infants with sudden rash may have febrile seizures during high fever. It has been estimated, that the infection from type 6 herpes virus is responsible for one third of all cases of febrile seizures in infants of 6 to 18 months.
How is the diagnosis made?
The doctor usually makes a diagnosis from the history, the age, and the clinical picture. Only when hospitalization for seizures or high fever is required may tests need to be carried out, in order to exclude other more serious diseases (bacterial infection, urinary tract infection, meningitis etc.).
How is sudden rash treated?
The only thing needed in the vast majority of cases is care at home with antipyretics, breastfeeding, and hydration. In rare, non typical cases, or in case of complications, the child is referred to the hospital for further examination.
What is the outcome of sudden rash?
Sudden rash usually has an excellent outcome, without any immediate or future impact. Even in most cases of febrile seizures, the outcome is good, and there are no chronic complications or seizure recurrences (epilepsy).
Is there a vaccine for the disease?
Not for the time being.
Stelios Papaventsis MRCPCH DCH IBCLC 2012