Pathogenesis of the rubella exanthem: distribution of rubella virus in the skin during rubella with and without rash.

In a previous assessment of the role of rubella virus in the pathogenesis of the rubella exanthem, virus was consistently isolated from cell cultures of skin biopsy specimens of the rash, and it was concluded that presence of virus in the skin was essential to evolution of the rash. For determination of whether virus is present in the skin only in association with rash, punch biopsies were performed concurrently on areas of skin with and without rash. Among paired skin specimens of 16 patients, virus was isolated from sites of rash in 12 and from the uninvolved skin in 10. In another patient, shown by serologic response and recovery of virus from the pharynx to have rubella without a rash, virus was also isolated from the skin. It is concluded that rubella virus is widely disseminated in the skin of patients with rubella irrespective of the presence or distribution of the rash, and that the presence of virus in the skin, although a constant feature of the disease, is only one of the factors involved in the pathogenesis of the exanthem.