Herpes simplex virus in childhood erythema multiforme.

Although an association between herpes simplex virus (HSV) infection and erythema multiforme (EM) minor has been documented in adults, this has not been reported in the pediatric population. This study assessed the potential role of HSV infection in the pathogenesis of EM minor in children. Erythema multiforme skin lesions from 20 children, aged 1 to 16 years, were examined for the presence of HSV by using the polymerase chain reaction. The children included all fit strict clinical criteria for EM minor. Ten had a clinical history of an antecedent herpes infection ("herpes-associated EM"), and 10 did not ("idiopathic EM"). Herpes simplex virus DNA was detected in skin lesions of 8 of 10 children with herpes-associated EM and in 8 of 10 with idiopathic EM. Control skin biopsies from children with other bullous inflammatory diseases were negative. In addition, no HSV could be detected in a biopsy of normal uninvolved skin of a child in whom HSV was present in lesional skin. In situ hybridization on selected biopsies by means of an HSV-specific riboprobe confirmed the presence of HSV and localized it to the epidermis. It is concluded that HSV is a significant precipitating factor for EM minor in children, as it is in adults, and that clinicians should maintain a high index of suspicion of HSV even in the absence of a known history of herpes infection.