Published on 19/03/2015 by admin
Filed under Dermatology
Last modified 19/03/2015
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Michael Romano, Jeffrey Mailhot and Karen Wiss
Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports
Rubella (German measles, 3-day measles) is usually a mild disease of low-grade fever, generalized erythematous macules and papules, and generalized lymphadenopathy. It is caused by an enveloped RNA virus of the Togaviridae family.
In children, there is typically no prodrome. In adolescents and adults, a prodrome of fever, malaise, sore throat, nausea, anorexia, and generalized lymphadenopathy is often seen. The erythematous pink macules and papules start on the face and neck and spread down and out in a centrifugal fashion over 1–2 days. These lesions disappear in 2–3 days. Forschheimer spots, an enanthem consisting of petechiae on the hard palate, may accompany the rash.
Rubella is a self-limited illness. The treatment is generally supportive. Teenagers and adults may experience transient polyarthralgia and polyarthritis. Thrombocytopenia and encephalitis are extremely rare complications. During the first trimester of pregnancy, maternal rubella can result in fetal death or congenital rubella syndrome. The main fetal anomalies include ophthalmic disease (cataracts, glaucoma, microphthalmia, and chorioretinitis), sensorineural deafness, cardiac abnormalities (patent ductus arteriosus, atrial septal defects, ventricular septal defects), pulmonic stenosis, and blueberry muffin lesions (extramedullary hematopoiesis).
It can be difficult to distinguish rubella from other viral exanthems, in particular enteroviruses. Rubella also mimics measles, parvovirus B19, human herpesvirus (HHV)-6, and arboviruses. It is essential to differentiate infection between these viruses during pregnancy. Virus identification by culture is available. In congenital infections, rubella can be isolated from the blood, urine, cerebrospinal fluid, and the posterior pharynx. In postnatal infections, the virus is harbored in the nasopharynx. Amplification is accomplished by reverse transcription polymerase chain reaction (RT-PCR). Viral serology is also available for diagnosis. Both serum IgM and seroconversion of convalescent IgG with a fourfold increase in titer suggest recent infection. A more reliable diagnosis is obtained by both RT-PCR and serology, which can detect virus on day 0 of rash eruption. Microarray technology is a cheap and promising future methodology for diagnosis of acute infection. Children with rubella should be excluded from school for 7 days after onset of the rash. Rubella vaccine is recommended in combination with the measles and mumps vaccine, with or without the varicella vaccine (MMR or MMRV), at 12–15 months of age with a second dose at 4–6 years. However, an increased risk of febrile seizures has been reported with the combination MMRV vaccine. Post-pubertal females can be tested for rubella IgG and vaccinated if necessary. The vaccine contains live virus and should not be given to pregnant women.
Viral culture
Serology (acute IgM or acute and convalescent IgG)
PCR
Confirmation of rubella within 4 days of rash onset: comparison of rubella virus RNA detection in oral fluid with immunoglobulin M detection in serum or oral fluid.
Abernathy E, Cabezas C, Sun H, Zheng Q, Chen M, Castillo-Solorzano C, et al. J Clin Microbiol 2009; 47: 182–8.
On days 1 and 2, rubella infection was confirmed best by RT-PCR. On days 0, 3, and 4, serum IgM detected rubella infection. The most sensitive and specific testing for acute rubella infection would be to combine these methodologies within 1 week after the exanthem eruption.
A protein microarray immunoassay for the serological evaluation of the antibody response in vertically transmitted infections.
Ardizzoni A, Capuccini B, Baschieri M, Orsi C, Rumpianesi F, Peppoloni S, et al. Eur J Clin Microbiol Infect Dis 2009; 28: 1067–75.
Enzyme immunoassays are recommended as the ‘gold standard’ for rubella IgM and IgG detection. This study suggests that microarray technology offers a cheaper and more reliable diagnostic test which may be applicable for multiple congenital diseases.
The epidemiological profile of rubella and congenital rubella syndrome in the United States, 1998–2004: the evidence for absence of endemic transmission.
Reef SE, Redd SB, Abernathy E, Zimmerman L, Icenogle JP. Clin Infect Dis 2006; 43: S126–32.
Since the advent of the national rubella vaccination program, epidemiologic evidence strongly supports that rubella virus is no longer endemic in the US.
Observational safety study of febrile convulsion following first dose MMRV vaccination in a managed care setting.
Jacobsen SJ, Ackerson BK, Sy LS, Tran TN, Jones TL, Yao JF, et al. Vaccine 2009; 27: 4656–61.
Though MMRV and MMR + V have similar immunogenicity, MMRV has demonstrated increased side effects, most notably febrile convulsions in children on days 5–12 after vaccination.
Roseola infantum (exanthem subitum, sixth disease) is a disease of high fever in a well-appearing child with an exanthem of pink macules and papules upon defervescence. It is caused by infection with HHV-6 or -7.
Roseola is an illness of children between 6 and 36 months of age. The first sign of illness is a high fever (>39.5°C) that persists for 3 to 7 days, followed by an exanthem that spreads centrifugally from the neck, lasting hours to days. Typically, no treatment is necessary and the illness resolves in a few days. Febrile seizures are common in infants during the febrile phase, usually requiring emergency room care.
Identification of HHV-6 or -7 is difficult because most infections are asymptomatic. Culture from peripheral blood is available in specialized facilities but is of limited use due to slow turn-over. High population seroprevalence (~95%) also renders serology less useful. Seroconversion of convalescent IgG with a fourfold increase in titer is more indicative of acute infection. However, there is considerable antibody cross-reactivity between HHV-6, -7, and cytomegalovirus (CMV). Viral DNA detection by nucleic acid amplification of whole blood, serum, or plasma is the current method of diagnosis, though standardized methods of measurement are yet to be determined. Recent studies suggest that PCR alone cannot reliably distinguish between active and latent infection; a multiple assay approach is more sensitive and specific.
Most individuals harbor HHV-6 and -7 in their saliva, while only 1% of the population carries chromosomally integrated viral DNA. In the immunocompromised, viral reactivation frequently causes severe disease such as fever, bone marrow suppression, hepatitis, pneumonia, lymphoproliferative disorders, and encephalitis. In these patients, ganciclovir and foscarnet
Treatment of Skin Disease Comprehensive Therapeutic Strategies 4e
Antipyretics: acetaminophen (paracetamol), ibuprofen
Analgesics: non-steroidal anti-inflammatory drugs
School avoidance for 7 days
Immunization
