[Chronic exanthema in a child with congenital rubella]

Since congenital rubella has become extremely uncommon following the introduction of rubella vaccination, cutaneous signs are currently rarely reported.

An infant, presenting congenital rubella (seroconversion of the mother for rubella at 11 weeks' amenorrhoea), presented diffuse exanthema between the ages of seven and 24 months. In a setting of congenital rubella syndrome, the infant presented psychomotor retardation, deafness, hypoplasia of the pulmonary artery and under-nourishment. Humoral and cell-mediated immunodeficiency was also noted.

The cutaneous signs of congenital rubella were first described in the 1960s and 1970s; they are rare and appear after a symptom-free period before resolving spontaneously several months later. Standard findings include chronic exanthema of the face and extremities associating reticulated erythema and pigmented macular papules. Exanthema indicates chronic and persistent viral infection, a common situation in newborn babies and infants following maternal-foetal infection. The persistence of viral infection in infants is attributed to immature cellular immunity, which would otherwise either eradicate the virus or ensure passage to the latency phase. In the present case, there was also relative humoral immunodeficiency resulting from foetal rubella infection. The symptom-free interval before the onset of rash and other clinical signs may be due to the relative transient protection afforded by the presence of maternal immunoglobulines G.