Rubella (German Measles)

Rubella is a mild viral illness that, because of its devastating effects on the developing human fetus, is recognized as a major public health issue.
The incidence of rubella has declined markedly since mass immunization for rubella began in 1969.

The rubella virus is an RNA virus of the Togaviridae family and is transmitted via respiratory droplets.
The incubation period is 16 to 18 days.
Humans are the only known natural hosts where initial infection occurs in the nasopharyngeal mucosa.

Rubella presents with a mild prodromal illness of fever, headache, upper respiratory symptoms, and lymphadenopathy.
The prodrome is often subclinical in children, but tends to be more severe in older patients.
One to five days following the prodrome, the exanthem appears as discrete pink to red macules and papules on the face that spreads to the trunk and extremities within 24 hours (cephalocaudal direction; Fig. 7.3).
Lesions may coalesce to form an erythematous rash reminiscent of scarlet fever.
The eruption is characteristically short-lived, fading in 1 to 3 days in the same order it appeared sometimes accompanied by fine, branny desquamation.
Petechiae may also be present on the soft palate and are called Forschheimer spots.
The exanthem is often accompanied by tender lymphadenopathy especially of the postauricular, suboccipital, and posterior cervical lymph nodes.
Constitutional symptoms usually resolve within 24 hours of the onset of the rash but in some cases the lymphadenopathy persists for weeks.
The eruption may be pruritic, particularly in adults.

The clinical features of rubella are not distinctive enough to allow one to make the diagnosis with certainty based on the clinical presentation alone.
Although unnecessary in most cases, acute and convalescent antibody titers (IgM and IgG) can confirm the diagnosis. These tests are important in pregnant women who may have been exposed to rubella.

Differential Diagnosis

Measles

Roseola

A high prodromal fever occurs in the absence of other symptoms.
The morphologic appearance and duration of the exanthem are similar to those of rubella.

Erythema Infectiosum

Scarlet Fever

Drug Reaction

Management

No specific therapy is available. When necessary, supportive care including antipyretics or anti-inflammatory medications for arthralgias should be provided.
Rubella immunization is recommended for all children as an initial dose at 12 to 15 months of age and a second dose at 4 to 6 years of age.
Infected patients should be isolated from susceptible persons.

Helpful Hint

Rubella immunization should be well documented in women of childbearing age; if antirubella antibody titers are negative, rubella immunization should be given.

Complications

Complications are rare.
Infection during the first 20 weeks of pregnancy can result in fetal death or the congenital rubella syndrome that is characterized by cataracts, deafness, and congenital CNS and heart defects.