Viral exanthems

Abstract

By the early 20th century, physicians had formally recognized measles, rubella, erythema infectiosum, and roseola infantum as distinct disease entities on the basis of clinical and epidemiologic features. These four diseases are collectively referred to as the classic viral exanthems. The advent of modern virology enabled physicians to search for and eventually find the virus responsible for each of the classic exanthems. As more viral agents were discovered, it was found that many other viruses were capable of producing a morbilliform exanthem with human infection. During the last half of this century, there has been an explosion of new knowledge regarding viral agents that produce exanthems, with four new agents discovered within the past 5 years. In 1992, more than 50 different viruses capable of producing an exanthem have been identified and include enteroviruses (echoviruses, coxsackieviruses), herpesviruses (Epstein-Barr virus, cytomegalovirus, herpes simplex virus, human herpesvirus 6), hepatitis viruses (A, B, C, D, and E), respiratory syncytial virus, adenoviruses, mumps virus, reovirus, and human immunodeficiency virus. Herpes simplex virus (HSV) has been included because of the recent finding of HSV antigens and nucleic acids in the skin lesions of erythema multiforme minor (EM minor), supporting classification of EM minor as an HSV exanthem. Today, the newer exanthems are more likely to be seen by the consulting physician because of the marked reduction in the incidence of measles and rubella with widespread immunization. Specific serologic and virologic tests are available to the clinician to distinguish one viral exanthem from another.