What Are the Different Types of Pediatric Emergency Care?

Exanthema subitum (ES), also known as roseola infantum (RI), is a common fever and rash of infants and young children caused by human herpes virus type 6 and 7 infections. It is characterized by a sudden decrease in heat after 3 to 5 days of fever, a rose red maculopapular rash on the skin, a reduction in the condition, and a rapid recovery without complications.

Basic Information

nickname: Baby roseola
English name: exanthema subitum
English alias: roseola infantum

Visiting department: Pediatrics
Multiple groups: Infants
Common causes: Caused by human herpes virus type 6 and 7 infections
Common symptoms: After 3 to 5 days of fever, the temperature suddenly drops, and erythema rosea occurs

Causes of acute rash in young children

Human herpes virus type 6 (HHV-6) is the main cause. Most ES are caused by HHV-6B infection, and rarely caused by type A infection. In infants with acute rash and febrile diseases, type B infection is more common, and in immunosuppressed patients, both types of infection are visible. Other rare causes are human herpesvirus 7 (HHV-7), coxsackieviruses A and B, ecovirus, adenovirus and parainfluenza virus1.

HHV-6 has the typical morphological characteristics of herpesviruses. The virus particles are round and consist of 162 capsids with a 20-hedral symmetrical nucleocapsid with a diameter of 90 110nm. The outer layer is composed of a cortical layer with a thickness of 20 40nm; the outermost layer is covered with a lipid membrane with irregular glycoprotein protrusions on the surface. The core is a linear double-stranded DNA wrapped around a core protein to form an axial filament; the mature released virus particles are 180-200 nm in diameter.

HHV was isolated from the peripheral blood T lymphocytes of healthy adults for the first time in 1990, and the virus has been isolated from patients with chronic fatigue syndrome since then. Virus particles are about 200 nm in diameter. HHV-7 has a capsule. It belongs to -herpesvirus family with HHV-6 and CMV.

Clinical manifestations of infantile rash

The incidence of infection is mostly within the age of 2 years, and most often within the age of 1 year.

Fever

The incubation period is 1 to 2 weeks, with an average of 10 days. Suddenly high fever without prodromal symptoms, body temperature above 39 ~ 40 , early fever may be associated with convulsions. In addition to the lack of appetite, the general mental state of the children did not change significantly, but there were a few children with nausea, vomiting, cough, scleritis, swelling around the mouth and hematuria, very few drowsiness, convulsions, etc. Mild congestion and mild swelling of the lymph nodes in the head and neck and occipital region are manifested as disproportionately high fever and mild symptoms and signs.

Rash

After 3 to 5 days of fever, the temperature suddenly drops, the body temperature drops to normal within 24 hours, the rash develops at the same time or later, the rash is red maculopapular rash, scattered, the diameter ranges from 2 to 5 mm, and the pressure fades, rarely Integration. The rash usually occurs first in the face and neck and trunk, and then gradually spreads to the proximal extremities. After 1 to 2 days, the rash subsided without leaving any traces, and there was no desquamation and pigmentation. In some children, erythema may appear in early ptosis, and the rash does not need special treatment, and it can resolve on its own.

3. Other symptoms

Includes eyelid edema, anterior bulge, runny nose, diarrhea, and loss of appetite. Some children have enlarged lymph nodes in the neck.

Infant rash check

The diagnosis is mainly based on the detection of serum anti-HHV-6 and anti-HHV-7 antibodies. Viral DNA can also be detected by virus isolation or PCR (polymerase chain reaction).

Blood test

On the first or second day of onset, the white blood cell count can increase, but it decreases significantly after the rash, and the lymphocyte count increases, up to more than 90%.

2. Virus isolation

Virus isolation is the definitive diagnosis method for HHV-6 and 7 infections. HHV-6 and 7 can proliferate in fresh umbilical cord blood monocytes or adult peripheral blood monocytes. However, it is necessary to add phytohemagglutinin (PHA), IL-2, dexamethasone and other substances to the culture medium. The infected cells developed lesions around 7 days, and the cells showed polymorphism, nuclear shrinkage, and multinucleated cells. Infected cells can continue to survive for 7 days after lesions appear, and uninfected cells die within 7 days of culture. Because virus isolation and culture are time-consuming and not suitable for early diagnosis, they are generally only used for laboratory research.

3. Detection of viral antigens

Viral antigen detection is suitable for early diagnosis, but the duration of viremia is short, and it is difficult to take samples in time. Currently, immunohistochemical methods are widely used to detect viral antigens in cells and tissues. Antigen positive results can be used as a basis for diagnosis.

4. Determination of viral antibodies

The ELISA method and indirect immunofluorescence method for the determination of HHV-6, 7 IgG, and IgM antibodies are currently the most commonly used and easiest methods. IgM antibody positive, high titer IgG, and 4-fold increase in recovery IgG antibodies can all indicate the presence of HHV-6 and 7 infections. When an IgM antibody or an IgG antibody is detected from the cerebrospinal fluid, it indicates the presence of a central nervous system infection. IgM antibodies are generally produced 5 days after infection and can last for 2 to 3 weeks, while IgG antibodies are produced 7 days after infection and reach a peak after 4 weeks, which can last for a long time. However, because there is a certain antigen cross between herpes viruses, other herpes virus infections can also cause increased antibodies, which can be identified by anti-complement immunofluorescence tests.

5. Viral nucleic acid detection

HHV-6 and 7DNA can be detected by nucleic acid hybridization and PCR. Because HHV-6 and 7 both have latent infections, sometimes the DNA of the virus is detected and it is not possible to determine whether they are latent or activated. Quantitative and semi-quantitative PCR can be used to determine the amount of DNA to determine if there is an active infection. High concentrations of viral DNA suggest the presence of active infections.

6. Other auxiliary inspections

Normal cases do not require special examinations. X-ray chest radiographs and electrocardiograms can be performed if necessary.

Diagnosis and differential diagnosis of acute rash in young children

Suddenly high fever in infants under 2 years of age, no other systemic symptoms, rash occurs when the fever subsides, this disease should be considered. The disease needs to be distinguished from pneumococcal sepsis and measles, rubella, and Kawasaki disease. It is more important to identify rubella, because the two rashes are similar, but the fever of children with rubella is not high, the skin rash is accompanied by fever, and the enlargement of lymph nodes behind the ear and occipital is more obvious. In children, acute rash is a fever that erupts after 3 to 5 days.

Early childhood rash treatment

The disease should focus on general treatment and strengthen care, mainly symptomatic treatment. Mild children can rest in bed and be given a moderate amount of water and a nutrient-rich digestible diet. When the fever is high, you can give a physical cooling or a small amount of antipyretics, crying and irritability, try sedation; convulsions, and stop panic in time. Antipyretics and symptomatic treatment. However, for immunodeficiency infants or severe cases, antiviral treatment is needed, and there are no very certain antiviral drugs.

Prognosis of infantile rash

The disease has a good prognosis, and serious complications rarely occur. It has been reported that children may develop HHV-6 encephalopathy, hepatitis, and hematopoietic syndrome.

Early childhood rash prevention

Isolate the child until 5 days after the visit. The disease is not highly contagious, and preventive measures are the same as those for respiratory diseases.