Other viral infections of the skin

Abstract

Viral infections of the skin are common at any age. This chapter discusses smallpox viruses, picornaviruses, classical infectious diseases, and paraviral infections. While real smallpox is no longer important except for bioterrorism, cowpox (orthopox viruses) as well as parapox virus infections of Milker's nodule and orf should also be considered for skin infections. The most common smallpox virus infection is Mollusca contagiosa (parapox virus), which is associated with atopy in childhood and immunosuppression, such as AIDS, in adulthood. Enteroviruses and parechoviruses, which belong to the picornaviruses, trigger distinct exanthemas such as the classical and atypical hand-foot-mouth disease and the human parechovirus-3 exanthema, which is characteristic in infancy. While most classical exanthemas in childhood are directly attributable to infection by the pathogens, paraviral exanthemas are to be understood as a response of the immune system. Of these, papular-purpurpuric gloves-and-socks syndrome, asymmetric periflexurall and unilateral mediothoracic exanthema, as well as eruptive pseudoangiomatosis and eruptive hypomelanosis are discussed.