INJURIES TO SKIN AND SUBCUTANEOUS TISSUE
Injuries that violate the continuity of the skin and subcutaneous tissue can occur as a result of trauma or from various environmental exposures. Environmental exposures that damage the skin and subcutaneous tissues include caustic substances, exposure to extreme temperatures , prolongedof the skin allows the entry of organisms that can lead to local or systemic infection.
Traumatic Injuries Traumatic wounds include penetrating, blunt, and shear forces (sliding against a fixed surface), bite, and degloving injuries. Sharp lacerations, bullet wounds, “road rash” (injury from scraping against road pavement), and degloving injuries should be treated by gentle cleansing, d´ebridement of all foreign debris and necrotic tissue, and application of a proper dressing. Dirty or infected wounds should be left open to heal by secondary intention or delayed primary closure. Clean lacerations may be closed primarily. Road rash injuries are treated as second-degree burns and degloving injuries as thirddegree or full-thickness burns. The degloved skin can be placed back on the wound like a skin graft and assessed daily for survival. If the skin becomes necrotic, it is d´ebrided and the wound is covered with split-thickness skin grafts.
Radiation Exposure Acute radiation injuries such as those that occur in an industrial accident are devastating. The dose of radiation exposure is oftentimes lethal. In addition to the development of skin lesions (cutaneous radiation syndrome), patients suffer from gastrointestinal hemorrhage, bone marrow suppression, and multiorgan system failure. The most notable industrial radiation exposure accident occurred in 1986 at the Chernobyl nuclear power plant. Of the 237 individuals initially suspected of being exposed, 54 suffered from cutaneous radiation syndrome. The severity of symptoms ranged widely and included xerosis (dry skin), cutaneous telangiectasias and subungual splinter hemorrhages, hemangiomas and lymphangiomas, epidermal atrophy, disseminated keratoses, extensive dermal and subcutaneous fibrosis with partial ulcerations, and pigment changes (radiation lentigo). To date, no cutaneous malignancies have been noted. Solar or ultraviolet (UV) radiation represents the most common form of radiation exposure. The ultraviolet spectrum is divided into UVA (400–315 nm), UVB (315–290 nm), and UVC (290–200 nm). Regarding skin damage and development of skin cancers, the only significant wavelengths are in the ultraviolet spectrum. The ozone layer absorbs UV wavelengths below 290 nm, thus allowing only UVA and UVB to reach the earth. UVB is responsible for the acute sunburns and for the chronic skin damage leading to malignant degeneration, although it makes up less than 5 percent of the solarUVradiation that hits the earth. The treatment of various malignancies oftentimes includes radiation therapy. Given the basis of this therapy to act on rapidly dividing cell types, the skin and subcutaneous tissue are significantly affected. Acute radiation changes include erythema and basal epithelial cellular death. Dry desquamation may proceed to moist desquamation. With cellular repair, permanent hyperpigmentation is observed in the field of radiation. Chronic radiation changes begin at 4–6 months and are characterized by a loss of capillaries as a result of thrombosis and fibrinoid necrosis of vessel walls. This fibrosis and hypovascularity are generally progressive, which eventually may lead to ulceration because of poor tissue perfusion