Recent advances in pediatric infectious diseases and their impact on dermatology.

The past five years have seen numerous advances in the field of pediatric infectious diseases, and many of these have a substantial impact on the practice of dermatology. We review some of these advances and discuss their implications on etiology, diagnosis, therapy and complications of some relatively common conditions. The etiologic agent of exanthum subitum (roseola infantum) has been clearly implicated as a herpesvirus-6. Although in the classically described situation high fever in a young child is followed by defervescence and rash, two new scenarios have been described associated with this virus. The first is fever without rash and the second is rash without fever. The etiologic agent of erythema infectiosum ("slapped cheek") has been shown to be a human parvovirus B19. The virus has also been associated with aplastic crises (in hemoglobinopathies), hydrops fetalis, and a syndrome of subacute arthralgias in women. The etiologic agent in cat-scratch disease has recently been shown to be a small pleomorphic bacillus that also can produce pyogenic granuloma-like lesions in patients with acquired immunodeficiency syndrome. The number of cases of congenital syphilis, particularly in large cities, is increasing tremendously. Many of these infants have received no prenatal care because of drug abuse problems in their parents. Finally, we describe the changing etiology of impetigo that is predominantly associated with Staphylococcus aureus. We further describe the growing resistance to erythromycin and several new erythromycin drug-drug interactions.