1.3. Host immune defenses The competence of the host immune system plays a major role in determining which organisms may establish skin and soft tissue infections. The skin is the single largest organ in the body. Intact skin is the most important component in host defense against invasion from organisms in the external environment. Among the causes of breakdowns in this component of host defense are trauma, systemic illnesses affecting the skin (e.g. pedal edema and venous stasis causing “microbreaks” in skin), insertion of organisms beneath the skin by arthropod vectors and iatrogenesis (e.g.: surgery, intravenous catheter placement). Breakdowns in the skin barrier, or lack thereof, are important considerations in assessing risk for specific infections. Once organisms have penetrated beyond the superficial epidermis, they encounter components of the innate and adaptive immune response including dendritic cells, macrophages, neutrophils and T and B lymphocytes. Specific deficiencies in any one or more of these components of the
This is the end of the preview. Sign up
access the rest of the document.