Chickenpox (synonyms: chicken pox; varicellae; varicella; variola emphysematica [varicella]; variola hybrida [varicella]; variola illegitima [varicella]; variola notha [varicella]; variola spuria [varicella]; varicella (chickenpox); varicella; ICD-10 B01.-: Varicella [chickenpox]) is an infectious disease caused by the varicella virus (VCV; VZV), which is one of the childhood diseases. Varicella zoster virus (VZV) belongs to the Herpesviridae family, the Alphaherpesvirinae subfamily, and the Varicellovirus genus. In addition to chickenpox, the virus is also responsible for shingles (HZV; herpes zoster). Humans currently represent the only relevant pathogen reservoir. Occurrence: The infection occurs worldwide. The contagiousness (infectiousness or transmissibility of the pathogen) is high. The contagion index is 90%. More than 95% of adults have antibodies against the virus. The virus remains in the body for life, which is why reactivations can lead to zoster, but these usually occur after the age of 50. The disease occurs more frequently in winter and spring. Transmission is aerogenic (droplet infection in the air) or through contact with the vesicular contents and crusts containing the virus. Transmission from mother to unborn child is relatively rare, but when it occurs, it can lead to the so-called fetal varicella syndrome. The incidence (frequency of new cases) of chickenpox infection during pregnancy is generally given as 2-3 per 1,000 pregnancies. Caution!Zoster (shingles) can also be a source of infection for varicella infection (pregnant women!) The incubation period (time from infection to onset of disease) is 8-28 days (usually 14-16 days).
Symptoms – complaints
Leading symptoms
- Itchy exanthema (rash) with papules, vesicles, and crusts (scabs) that are in various stages of development (stellate); usually occurs first on the face and trunk of the body. The lesions (“damage”) can also spread to mucous membranes and hairy scalp.
Associated symptoms
- Fever
Affected individuals usually do not feel particularly limited in their general well-being. After about two to three weeks, the disease is over.
Special features in pregnancy
Although most women have already undergone an infection with chickenpox as a child and thus acquired lifelong immunity, nearly one in 20 women is not immune. If the expectant mother becomes infected with chickenpox without having undergone infection as a child, the disease can be transmitted to the unborn child via the placenta (placenta) (transplacental fetal infection). In early pregnancy (first and second trimester/third trimester), abortions (miscarriages) may occur. Fetal varicella syndrome (FVS) is to be expected in case of infection up to the 20th SSW. Possible consequences for the unborn child if infected in the first and second trimester (third trimester of pregnancy) are:
- Skin lesions with segmental spread (scarification, ulcers, scars).
- Ocular involvement (microphthalmia, enophthalmia, chorioretinitis, cataract, anisocoria, nystagmus, optic atrophy).
- Neurological diseases and malformations (encephalitis, cerebral atrophy, spinal cord atrophy, microcephaly, limb paresis, seizures, Horner’s syndrome.
- Skeletal anomalies (skeletal hypoplasias: hypoplastic extremities).
The lethality of fetal varicella syndrome is approximately 25-30% in the first months of life. Neonatal chickenpox, i.e. chickenpox in the first 12 days of life of a newborn, also indicate transplacental infection. If maternal (mother’s) chickenpox infection occurs 3 weeks before to 2 days after delivery, the risk of infection during this period is 25-50%.If the mother develops the exanthema (rash) between days 4 and 5 before delivery or on day 2 after delivery, neonatal chickenpox results in death in up to 20% of affected cases. Neonatal chickenpox within the first 4 days after birth usually proves mild.A fatal outcome has been reported in 2% of cases when newborn chickenpox occurs between 5 and 10 to 12 days of age.If the infection occurs earlier than four days before birth, the child may receive antibodies from the mother, if she has already undergone infection with chickenpox, which significantly attenuates the course of the disease. In case of infection between the fourth day before and the second day after delivery, this is no longer possible. Vaccination is possible, but it can only be given before pregnancy if the child is still wanted. Note: In the absence of immunity and vaccination, the patient must be informed that conception should be avoided for 4 to 6 weeks after vaccination! (Contraception required)
Diagnostics
The diagnosis of chickenpox is made by means of a blood test.In the case of suspected infection or contact with a sick child, a blood test should be performed immediately.This is necessary to clarify the initial immunological situation, i.e., the question of whether there was already an infection in the past and therefore there is immune protection so that the unborn child cannot become ill or whether there is a fresh infection or no infection.Laboratory parameters 1st order – obligatory laboratory tests.
- Varicella zoster virus antigen detection (IgG, IgM, and IgA elisa).
Note: In Germany, a varicella-zoster virus seroprevalence (percentage of positive serological parameters (here: VZV) tested at a given time in a given population) of at least 96-97% is assumed. Caution!If there is no immune protection, a new blood test after two weeks is absolutely necessary to exclude a possible infection.
Benefits
For your child, only the initial infection is dangerous. Therefore, it is urgent to clarify whether you have already had chickenpox as a child.If you have not yet had chickenpox, you must avoid contact with people who have chickenpox – or shingles – and have regular blood tests if necessary.