Infections cutanées à poxvirus

Poxviruses are DNA viruses that infect humans and animals. Their strong tropism for the skin explains why skin lesions are consistently present in humans. Smallpox caused devastating epidemics in the past, with mortality rates of about 30%, but was eradicated in 1980 by mass immunization with the vaccinia virus. Orthopoxviruses, such as monkeypoxvirus or cowpoxvirus, cause vesicular eruptions that can be severe but are extremely uncommon. Orf disease and milkers’ nodules are caused by parapoxviruses that usually infect livestock. Both diseases manifest as pseudotumoral nodules over the limbs that clear spontaneously. Molluscum contagiosum presents as shiny umbilicated papules and is seen mainly in children and young adults. In patients with cell-mediated immune deficiencies, most notably due to HIV infection, molluscum contagiosum lesions are more common than in the general population, often profuse, and difficult to treat.