Immunodermatology and viral skin infection

The skin is the largest organ in the human body, acts as our fist line of defense, and has a sophisticated array of cells and signaling molecules to help protect the body from infection. Yet even with this sophisticated defense, viruses cause a range of cutaneous diseases in humans, many of which are widespread in the population and cause significant morbidity and mortality, along with psychological and financial repercussions. Each virus has unique mechanisms by which it evades the immune system, replicates, and spreads. Some viruses infect the skin directly while others gain access systemically first. Infections can be acute or subclinical and then resolve, while others are persistent or can remain latent for years. This spectrum of presentations is mirrored by an equally wide array of evasion tactics that the viruses use to manipulate and escape both the adaptive and innate immune responses. In addition to highlighting viral responses, particular attention is also paid to the local immune response generated in the skin. Five viruses will be discussed in detail: herpes simplex virus, varicella zoster virus, human immunodeficiency virus, molluscum contagiosum virus, and human papilloma virus; along with the latest information on the development and advancement of both therapeutic and prophylactic vaccines.