Exanthema Subitum
Everything about the causes, symptoms, and prognosis of this childhood viral disease characterized by fever and rash.
Symptoms and causes
Exanthema subitum, also known as roseola, is a viral disease that primarily affects infants between four months and two years of age. It can occur at any time of the year, although it is more frequent in spring and autumn.
One of the main clinical manifestations of roseola is the cutaneous eruption. Due to the historical classification of infectious diseases presenting with rash—an ordered list of six conditions—it is also known as the sixth disease (measles, scarlet fever, rubella, varicella, erythema infectiosum, and exanthema subitum).
Roseola is transmitted between humans through contact with saliva or blood and has an incubation period of five to fifteen days. Transmission does not occur during this period, but rather when symptoms become apparent.
The prognosis of exanthema subitum is very good, as it resolves spontaneously without complications in most cases.
Symptoms
Roseola presents with two very characteristic symptoms:
• High fever (39.5°C–40.5°C) lasting two or three days with no apparent cause.
• Rash that appears suddenly once the fever subsides. This eruption consists of pinkish macules that blanch with pressure. It typically begins on the chest and spreads to the face, abdomen, and sometimes the extremities. It generally disappears after one or two days.
In addition, some patients present irritability, nasal congestion, conjunctival and auricular erythema, pharyngeal irritation, or cervical lymphadenopathy.
Causes
Exanthema subitum is caused by human herpesvirus 6 (HHV-6)—type B in 99% of cases—and, to a lesser extent, human herpesvirus 7.
Risk Factors
The most relevant risk factors for roseola include:
• Age: most affected individuals are under two years old.
• Low antibody levels: it typically appears after four to six months of age, when infants do not yet have all their vaccinations and begin to lose the immunity acquired from the mother during pregnancy.
• Adults: it may occur in individuals who have not been previously exposed to the virus. It is uncommon after the age of 20.
• Contact with infected individuals.
Complications
Although uncommon, exanthema subitum can cause febrile seizures. Some immunocompromised patients may develop hepatitis or encephalitis.
Prevention
Roseola cannot be prevented, but the following practices reduce the risk of infection:
• Maintaining proper hygiene, especially washing hands with soap and water after coughing, sneezing, being around someone who is ill, or touching the eyes, nose, or mouth.
• Avoiding touching the eyes, mouth, and nose, as this facilitates viral entry into the body.
• Remaining isolated during the contagious period.
Which specialist treats exanthema subitum?
Exanthema subitum is diagnosed and managed within the specialty of Pediatrics.
Diagnosis
The diagnosis of exanthema subitum can be challenging, as fever with no apparent cause may be indicative of numerous conditions. The key is to consider the patient’s age and clinical signs—especially monitoring their evolution and confirming that the rash appears immediately after the fever subsides.
Blood Tests are used to confirm the diagnosis when there is uncertainty and other diseases need to be ruled out. Changes in white blood cells are essential, as during the febrile phase there is an increase in leukocytes (leukocytosis), whereas once the rash appears, leukocyte counts decrease (leukopenia), but lymphocytes and monocytes increase (lymphomonocytosis) and neutrophils decrease (neutropenia).
Treatment
As this is a benign viral infection, there is no specific treatment for exanthema subitum.
Relative rest and maintaining adequate hydration by drinking plenty of fluids are recommended. If the patient experiences discomfort or irritability, analgesics or antipyretics such as acetaminophen or ibuprofen may be administered.
