Chapter 10 - Cutaneous, Subcutaneous, and Deep Tissue Infections

Abstract

The cutaneous and mucosal barriers represent important components of our defense system against foreign substances, toxins, and infectious pathogens. Some commensal microorganisms may become opportunistic pathogens in certain circumstances including breaching of the skin or mucosal barriers; some may even become invasive of sterile sites (ie, bacteremia) leading to life-threatening consequences. Some infectious pathogens may produce exotoxins that exert a destructive effect in the epidermis, dermis, subcutaneous tissues, or the muscle. A particular set of toxins may activate systemic inflammatory responses with potentially catastrophic consequences leading to multiple organ failure, and often, death. Either through virulence factors or through inducing exuberant and uncontrolled inflammatory responses, some pathogens exert destructive features in human tissues. A prototypic example is the group A streptococci serotype M1T1 which is the most frequently isolated streptococci isolated from life-threatening invasive infections such as necrotizing fasciitis and streptococcal toxic shock syndrome. Infectious diseases of the skin may be divided into the following categories: impetigo, cellulitis, abscess, erysipelas, necrotic skin and soft tissue conditions (necrotizing cellulitis, necrotizing fasciitis, clostridial myonecrosis, Fournier’s gangrene; cutaneous and subcutaneous consequences of human or animal bites; and infections associated with animal contact).