Chapter 37 SKIN INTEGRITY AND WOUND CARE
The skin has several functions, which are largely concerned with protection of the body against infection, physical trauma and ultraviolet radiation. Any disorder that disrupts normal skin function will affect the efficiency with which it carries out its functions, and may place the physiological integrity of the individual at risk. The effects that disorders of the skin have on the individual range from being minor and temporary, to major and life threatening. Some serious skin disorders such as burns affect the individual to the extent that self-concept and body image are severely impaired. Wound management is a major role of the nurse. It is important that all nurses have a good knowledge of normal wound healing and the variances that can occur with ageing and disease processes. There is an abundance of literature on wound management and a vast array of wound-care products. The aim of this chapter is to assist the nurse unravel some of the confusion.
After I had open heart surgery, I was very concerned about the scars on my chest. I thought I would never be able to wear a low-cut blouse again. But the nurses explained to me that with the new dressings available today the wound will heal very well and the scar will become less noticeable over time.
THE INTEGUMENTARY SYSTEM
The integumentary system consists of the skin and its appendages; the hair, nails, sweat and sebaceous glands. The skin (or integument) is the largest organ of the body, covering about 7500 cm2 of surface area in an average adult (Figure 37.1). It is a protective barrier to the outside world, plays a vital role in homeostasis, and also provides a major means of communication through touch and sensation. The appendages of the skin — hair, nails and glands — arise from the epidermis but are present in the dermis.
STRUCTURE OF THE SKIN
The skin is comprised of two basic layers: the epidermis and dermis. Under the dermis is a layer of adipose tissue called subcutaneous tissue. While this layer is not considered to be part of the skin, subcutaneous tissue does protect and insulate the deeper tissues.
The epidermis
The epidermis is the thin outermost layer and is composed of epithelial cells arranged in layers of stratified epithelium. The number of layers varies according to the amount of wear and tear experienced; for example, there are many more layers on the soles of the feet and the palms of the hands than there are between the toes and the fingers.
The epidermis is divided into two layers. The horny layer (stratum corneum) is the uppermost layer, and consists of about 30 layers of dead, flattened keratinised cells. These keratinocytes contain a waterproof hard protein substance called keratin. Keratin’s waterproofing properties protect the body and prevent escape of fluid from the deeper tissues. Keratin is also responsible for the formation of hair and nails. The germinative layer (stratum germinativum) is the deeper layer of the epidermis. It is here that new cells are constantly being formed and pushed upwards to replace cells that die and are rubbed off. Millions of new cells are produced daily and are pushed up away from the source of nutrition, to become part of the outermost layer.
Melanocytes are present in the germinative layer. Their function is to produce a brown pigment called melanin. Melanin gives colour to the skin and protects the body against the damaging effects of ultraviolet rays in sunlight. Brown-toned skin results when large amounts of melanin are produced, whereas light-toned skin results when the body produces less melanin.
The epidermis does not contain any blood vessels, but receives its essential substances from fluid that comes from the blood supply to the dermis. As cells are pushed towards the surface, away from the source of nutrition, they die and are eventually rubbed off. Thousands of dead epithelial cells are flaked off every day, which means that they are deposited on clothing and on every surface touched. They become part of the dust in a room, serve as food for mites, and harbour microorganisms. A person sheds about 0.5 kg of dead cells per year, much of which goes down the bathroom drain.
The patterns of lines and ridges in the epidermis are due to projections in the dermis called papillae. On the fingertips these patterns are the fingerprints, which are different in every individual. For this reason, fingerprints are useful for purposes of identification. Nails are formed from the stratum corneum and are composed of modified epithelium.
The dermis
The dermis consists of white fibrous tissue containing many elastic fibres. Elasticity of the skin is essential to allow for changes in the size of a part of the body without tearing, such as the abdominal area during pregnancy. In old age the fibres become less elastic, causing wrinkles and folds to appear in the skin. The following structures are contained in the dermis.
Network of blood vessels
The blood vessels transport blood containing oxygen and nutrients to the dermis and transport blood containing wastes such as carbon dioxide away from the dermis. The blood vessels also play a role in regulating body temperature. If the body temperature is elevated the dermal capillaries become engorged with blood, which allows loss of body heat from the skin surface through radiation. If the environmental temperature is low, blood vessels in the skin constrict, conserving body heat by reducing radiation from the body.
Nerve endings
The dermis has a rich nerve supply consisting of several types of nerve endings. Each type of nerve ending reacts to a different stimulus, such as pain, touch, pressure and temperature. Impulses are transmitted from the nerve endings to the brain for interpretation.
Hair follicles and hairs
Hairs grow from hair follicles, which are deep pouch-like cavities in the skin. Although hair follicles are present in most areas of the skin, they are not found on the palms of the hands or the soles of the feet. Hair is composed of modified epithelium and grows from roots deep in the follicles. The part of a hair projecting above the epidermis is called the shaft. Hair colour reflects the amount of pigment, generally melanin, in the epidermis. Hair is a protection from the elements and from trauma; for example, the scalp hair and eyebrows are barriers against sunlight, and the nasal hairs filter inhaled air.
Hair growth is influenced by the sex hormones oestrogen and testosterone. An excessive growth of hair is called hirsutism. Like other cells that compose the skin, the hair cells also become keratinised. The hair that we brush, blow dry and curl is a collection of dead keratinised cells. Hair colour is genetically controlled and is determined by the type and amount of melanin. The absence of melanin produces white hair. Grey hair is due to a mixture of pigmented and non-pigmented hairs. Red hair is due to a modified type of melanin that contains iron. Hair is important cosmetically. Hair loss can be very distressing for some people. The most common type of hair loss is male-pattern baldness. It is a hereditary condition characterised by a gradual loss of hair with ageing.
Arrector pili muscles
These are minute involuntary muscles, with one end attached to a hair follicle and the other end to the dermis. When these muscles contract, for example, during fear or exposure to cold, the follicles and hairs become erect. Contraction of the muscles also causes some elevation of the skin around the hairs, giving rise to the ‘goose pimple’ appearance. The contraction of the arrector pili muscles increases heat production. This response is called shivering.
Sebaceous glands
Sebaceous glands are small glands, most of which open into hair follicles. The glands produce sebum, which is an oily substance and a lubricant that keeps the skin soft and moist and prevents the hair from becoming brittle. Combined with sweat, sebum forms a moist, oily acidic film that is mildly antibacterial. During periods of increased hormonal activity, such as adolescence, sebaceous glands become very active and the skin becomes oilier.
Sweat glands
Sweat glands, which are widely distributed, are either eccrine or apocrine. Eccrine glands are present all over the body and produce a clear perspiration. Apocrine glands are found mainly in the axillary and genital areas, and secrete sweat that has a strong characteristic odour. Sweat glands are coiled in appearance, with a straight duct that releases sweat onto the surface of the skin through an opening called a pore.
Sweat glands play a part in regulating body temperature. They excrete large amounts of sweat when the external, or body, temperature is high. When sweat evaporates off the skin’s surface it carries large amounts of body heat with it. Sweat consists of water that contains sodium chloride, phosphates, urea, ammonia and other waste products. Under normal circumstances, the amount of sweat secreted by an individual is about 700 mL/day. Under some conditions, such as strenuous physical exertion or pyrexia, the amount can be increased to as much as 1500 mL/day. Much of the water lost through the skin evaporates immediately, so it is not noticeable and is called insensible perspiration. Sweat that makes the skin damp and is noticeable is called sensible perspiration.
FUNCTIONS OF THE SKIN
The major functions in which the skin and its appendages play a role are protection, thermoregulation, metabolism and sensory perception.
Protection
The skin is the first line of defence against the external environment. It provides a barrier to a variety of harmful agents, such as microorganisms, radiant energy and chemical substances. The skin acts as a barrier to harmful agents only as long as it remains intact. The waterproof quality of the outer layer prevents excess water absorption and abnormal loss of body fluids. The skin contains nerve endings that are sensitive to painful stimuli. The nerve endings transmit impulses to the brain that alert the individual that damage is occurring.
Thermoregulation
The skin plays a major role in the maintenance of constant body temperature. Blood conducts heat from internal structures to the skin for dissipation. The skin dissipates excess body heat by radiation, conduction, convection and evaporative cooling. Body temperature is controlled by the hypothalamus, which is the heat-regulating centre in the brain. This centre is sensitive to the temperature of the blood passing through it and also receives sensory stimuli from nerve endings in the skin that react to heat and cold (thermoreceptors). The hypothalamus in turn relays impulses requiring vasodilation and activation of the sweat glands (for cooling), or vasoconstriction and inhibition of sweat glands (for heat retention). Thus, the hypothalamus acts like a thermostat that initiates heat-losing activities when the body temperature begins to rise, and heat-retaining activities when the body temperature starts to fall.
Metabolism
The skin assists in the regulation of fluid and electrolyte balance by eliminating water and small amounts of sodium chloride through the sweat glands. Sweat consists of 99.4% water, 0.2% salts, and 0.4% urea and other wastes. In the presence of sunlight or ultraviolet radiation, the skin begins the process of forming vitamin D (calciferol), a substance required for absorbing calcium and phosphates from food.
Sensory perception
Through perception of a painful stimuli, the skin causes an avoidance reaction, while other receptors perceive sensations of pressure and touch. The skin is therefore an agent of communication between the outside environment and the body, as the activity of sensory nerve endings informs the individual of what is happening outside the body.
WOUND HEALING
Wound healing is a dynamic and complex process and consists of four stages: haemostasis, the inflammation stage, the reconstruction phase and the maturation phase. The process of wound healing begins at the moment of injury and can continue for some years.
HAEMOSTASIS
The first stage of wound healing is haemostasis, which has three components, vasoconstriction, platelet response and the biochemical response. Vasoconstriction is when the bleeding in the wound is arrested by spasm in the arteries, arterioles and capillaries.
The platelet response is commonly described as the formation of the platelet plug. When platelets come into contact with parts of a damaged blood vessel, such as collagen or endothelium, their characteristics change. They become larger and irregular in shape and stick to the collagen fibres in the wall of the vessels and to each other. The platelets release various chemicals — serotonin, prostaglandins, phospholipids and adenosine diphosphate (ADP)—which attract more platelets, which stick to the original platelets and form the plug. This platelet plug is very effective in preventing blood loss in a small vessel.
The biochemical component is the formation of a blood clot through the processes of the intrinsic and extrinsic clotting pathways, clot retraction and fibrinolysis. This is a complex process involving different clotting factors that are released from the damaged tissue. A clot is developed and retraction of the wound takes place.
The next stage of the healing process is termed tissue repair. This stage also has three phases — inflammation, reconstruction and maturation — which overlap each other and have varying time intervals.
THE INFLAMMATION PHASE
This phase begins the moment that injury is incurred. The capillaries contract and thrombose to facilitate haemostasis. Vasodilation of the surrounding tissues occurs in response to the release of histamine and other vasoactive chemicals. This process causes increased blood flow to the surrounding tissue, which produces erythema, swelling, heat and discomfort, such as throbbing. A variety of white blood cells called polymorphonuclear leucocytes arrives at the site of the wound as a defence response and is involved in the immune response to fight infection. Polymorphs, macrophages and their associated growth factors produce various local and systemic effects. This phase continues for about 3 days.
THE RECONSTRUCTION PHASE
This is a time of cleaning and temporary replacement of tissue. The polymorphs kill bacteria, and the phagocytic macrophages digest the dead bacteria and debris to clean up the wound. Dermal repair is necessary if the wound is one of full thickness. New blood capillaries are developed (angiogenesis) and granulation tissue, which consists largely of collagen, is laid down. Epithelial cells migrate over the granulation tissue from the surrounding wound edges, hair follicles, sweat or sebaceous glands in the wound. These cells are very fragile. When the wound is covered the epithelium begins to thicken to 4–5 layers, forming the epidermis. Wound contraction then occurs, reducing the overall size of the wound. This phase can continue for 2–24 days.
THE MATURATION PHASE
This is commonly known as the remodelling phase. The matrix of collagen cells is reorganised and strengthened. This phase can continue for about 24 days to 1 year. The wound is still at risk during this phase and should be protected.
HEALING INTENTIONS
When the wound has minimal tissue loss and the edges can be brought together by sutures or clips, as in a surgical wound, the wound is said to heal by primary intention, or first intention. Granulation tissue is not obvious. Healing by secondary intention occurs when wound edges cannot be brought together, as with a gaping wound. Granulation tissue fills in the wound until re-epithelialisation takes place and a large scar results. Third intention, or delayed primary intention, healing occurs when wound closure is delayed for a few days, so that an infected or contaminated wound can be debrided (dirt, foreign objects, damaged tissue and cellular debris are removed from a wound or burn to prevent infection and promote wound healing). Closure of contaminated wounds is usually delayed until all layers of wound tissue show no signs of infection, usually within 4–10 days. At other times some wounds need surgical intervention such as the application of skin grafts or flaps to speed the healing process and reduce the risk of infection. Clinical Interest Box 37.1 provides details on skin grafts.
CLINICAL INTEREST BOX 37.1 Skin grafts
Skin grafts speed up the healing process and reduce the risk of infection. Grafts may be partial or full thickness. Skin grafts are classified as:
TYPES OF WOUNDS
SEPTIC AND ASEPTIC WOUNDS
Clean wound
These wounds are made under aseptic conditions such as surgery, and heal by primary intention. These wounds generally do not require drainage.
Clean-contaminated wound
This is a wound made under aseptic conditions, but involving a body cavity that normally harbours microorganisms, such as the gastrointestinal, respiratory or urinary tract.
Contaminated wound
This term applies to a wound in which microorganisms are likely to be present, and includes open, traumatic and accidental wounds and surgical wounds in which a break in asepsis occurred.
Dirty wound
This term applies to traumatic wounds that are generally more than 4 hours old. Purulent discharge is evident. The wounds involve perforation of viscera and spillage of contents.
ACUTE AND CHRONIC WOUNDS
Acute wounds
Acute wounds in early stages are frequently not colonised with bacteria, but infection can become a complication. Although infection cannot always be prevented, care should be taken to minimise transmission by thorough aseptic technique when attending to the wound. Examples of acute wounds are those made by surgical incision or traumatic injury. An example of a surgical wound is a skin flap (refer to Clinical Interest Box 37.2).
CLINICAL INTEREST BOX 37.2 Skin flaps
A flap is a surgical relocation of tissue from one part of the body to another part to reconstruct a primary defect. This creates a secondary defect that will require skin grafting or primary closure.
Types of flaps
Skin, or cutaneous, flaps are grafts of tissue consisting of skin and superficial fascia. Composite tissue flaps are described according to the type of tissue they are composed of; for example, fasciocutaneous flap.
Flaps can be classified as free and pedicle. A free flap is the relocation of skin and subcutaneous tissue as a complete segment, with an anastomosis of the segment’s blood supply to vessels at the affected site. A pedicle flap is the surgical transfer of skin and subcutaneous tissue to another body site. Blood supply to the flap is maintained via a vascular pedicle attached to the body donor site.
Chronic wounds
Chronic wounds are rarely sterile. Microbial colonisation is usually present, predisposing the wound to infection. Clinical infection depends on the virulence of the bacteria and the resistance of the host. Clinical Interest Box 37.3 provides the differences between inflammatory response and infection. An example of a chronic wound is a venous leg ulcer.
CLINICAL INTEREST BOX 37.3 Recognising the differences between inflammatory response and infection
| Inflammation | Infection |
|---|---|
Wounds can be described according to the amount of damage done to the tissues:
CLASSIFICATION OF WOUNDS BY STAGES
Stage I
Observable pressure-related alteration(s) of intact skin, whose indicators, as compared to the adjacent or opposite area on the body, may include changes in skin temperature (warmth or coolness), tissue consistency (firm or boggy feel) and/or sensation (pain, itching).
Stage II
Partial-thickness skin loss involving the epidermis and/or dermis. The ulcer is superficial and presents clinically as an abrasion, blister or shallow crater.
Stage III
Full-thickness skin loss involving damage or necrosis of subcutaneous tissue that may extend down to, but not through, underlying fascia. The ulcer presents clinically as a deep crater with or without undermining of adjacent tissue.
PATHOPHYSIOLOGICAL INFLUENCES/EFFECTS AND MAJOR MANIFESTATIONS OF SKIN DISORDERS
PATHOPHYSIOLOGICAL INFLUENCES AND EFFECTS
The major factors that affect normal structure and functions of the skin can generally be classified into six categories:
Genetic factors
Genetic factors determine skin colour and the amount and distribution of hair. Congenital skin disorders include birthmarks, hypopigmentation (albinism) and a condition called ichthyosis, which involves excessive scaling or thickening of the outermost skin layer. Heredity also plays a role in predisposition to the development of acne and atopic dermatitis.
Idiopathic causes
Many skin disorders have no one known cause, for example, vitiligo and psoriasis. Other skin disorders may be associated with emotional or physical stress but there does not seem to be any one identifiable cause.
Hypersensitivity
Some individuals have a tendency to react adversely to contact with various substances, for example, when a substance is inhaled, ingested or comes in contact with the skin. Some allergic reactions are manifested in alterations in the skin; for example, reddening and itching of the skin may be side effects of certain medications.
Trauma
Damage to the skin can result from exposure to extremes of temperature, from prolonged pressure on the skin or from physical injuries resulting in lacerations, punctures or abrasions.
Neoplasia
Any abnormal growth of new tissue, whether benign or malignant, is called a neoplasm. Examples include calluses, which can develop on the toes from friction and chronic pressure, or keloid scarring, which can result after injury to the skin. Benign or malignant neoplasms may develop from any type of cell in the skin, but the melanocytes and keratinocytes are the cells most frequently involved. A mole (naevus) is a common type of benign skin tumour. Some benign epithelial cell lesions may develop into malignant neoplasms.
Infections and infestations
If the skin is broken and pathogenic microorganisms gain entry, infection may result.
Primary skin infections are commonly caused by bacteria, fungi and viruses. Secondary skin infections may occur in conditions such as stasis dermatitis, in which impaired circulation damages skin cells of the lower limbs.
Systemic infections, such as measles, chickenpox and some sexually transmitted diseases, also result in manifestations on the skin. Skin infestations occur when parasites such as lice or mites invade and subsist on the skin.
MAJOR MANIFESTATIONS OF SKIN DISORDERS
Various structural and functional changes accompany skin disorders.
Pruritus
Pruritus (itching) is one of the more common and distressing symptoms of a skin disorder. Pruritus is thought to result from a disruption in the skin nerve endings. Scratching to relieve pruritus can result in tissue damage and infection, thereby causing further discomfort.
Lesions
Depending on the type of skin disorder, one or a variety of lesions may be present. Observation of the patient includes assessing any lesions to determine their shape, size and distribution. Table 37.1 lists and describes the various types of skin lesions. Some types of lesions may discharge fluid, which is referred to as exudate.
| Term | Description | Examples |
|---|---|---|
| Bulla | Elevated, filled with clear fluid. Similar to a vesicle, but larger | Pemphigus vulgaris, drug eruptions, partial thickness burns |
| Comedo | A plug of secretion contained in a follicle | Acne |
| Crust | A superficial mass caused by dried exudate | Impetigo, eczema |
| Cyst | Encapsulated mass in the dermis or subcutaneous layer. May be raised or flat, and contain fluid or solid material | Sebaceous cyst |
| Erosion | Moist, red, depressed break in the epidermis. Follows rupture of a vesicle or bulla | Chickenpox |
| Excoriation | Superficial break in the skin | Scratches, abrasions |
| Fissure | Deep, linear, red crack or break exposing the dermis | Tinea pedis |
| Macule | Small circumscribed discolouration, e.g., red, white, tan or brown | Freckle, rubella, scarlet fever |
| Nodule | Circumscribed, elevated area — usually 1–2 cm in diameter | Ganglion, acne |
| Papule | Circumscribed, elevated, firm palpable area | Mole, wart, pimple |
| Plaque | Elevated, rough flat-topped areas | Psoriasis, seborrhoeic warts |
| Pustule | A vesicle or bulla containing pus | Acne, furuncle, folliculitis, impetigo |
| Scale | Mass of exfoliated epidermis | Dandruff, psoriasis |
| Scar (cicatrix) | Ranges from a thin line to thick, irregular fibrous tissue. May be white, pink or red | Healed surgical incision or wound |
| Tumour | Elevated, solid formation | Lipoma, melanoma, fibroma |
| Ulcer | Depressed circumscribed area involving loss of the epidermis, exposing the dermis, and may involve subcutaneous tissue | Decubitus ulcer, stasis ulcer |
| Vesicle | Circumscribed, elevated superficial area filled with clear fluid | Blister, herpes simplex infection, contact dermatitis |
| Weal | Transitory, elevated irregularly-shaped swelling of the epidermis | Urticaria, insect bites |
Alterations in sensation
In addition to pruritus, the individual may experience other abnormal skin sensations such as numbness, tingling, burning or pain.
Alterations in skin colour
Disorders of the skin may be accompanied by darkened areas of skin (hyperpigmentation), patches of pale skin (hypopigmentation) or inflammation. Burned skin may be reddened, blanched or charred, depending on the extent of the burn. Cold injuries can result in red areas, as in chilblains, or in extreme pallor, as in frostbite.
Alterations in skin temperature
In certain skin disorders such as bacterial infection the skin may feel hot to touch, whereas in other conditions such as frostbite the skin is cool to touch.
Alterations in texture
Abnormalities of texture, for example, roughness or hardness, may result from the presence of certain types of lesions such as scabs or papules. Scaling may occur, or the skin may be thick, wrinkled, or atrophied. Some skin disorders may result in areas of oedema; for example, injuries from heat or cold.
Presence of an odour
Certain skin disorders, particularly those that are accompanied by oozing lesions, may give rise to an offensive odour.
SPECIFIC DISORDERS OF THE SKIN
GENETIC DISORDERS
Genetic disorders are those that are present at birth, become evident soon after birth, or those that may be passed on to the next generation.
Acne vulgaris is a chronic inflammatory condition involving the sebaceous glands and the pilosebaceous follicles, particularly of the face. A blackhead forms and blocks the opening of a sebaceous gland, which becomes infected. Later, a pustule forms. This condition is most often present in adolescents and young adults. Familial tendencies are thought to contribute to the cause or exacerbation of acne. Other causative factors include endocrine imbalances, use of oral contraceptives, hormone therapy, emotional stress and lack of personal hygiene.
Ichthyosis is any one of several inherited conditions in which the skin is dry, hyperkeratotic and fissured, resembling fish scales. It usually appears at, or shortly after, birth. Ichthyosis vulgaris is the most common type and the least severe.
IDIOPATHIC DISORDERS
Idiopathic disorders are those in which no definite cause can be identified.
Psoriasis is a chronic skin disorder characterised by red patches covered by thick, dry, silvery scales. The lesions may be present on any part of the body but are more common on the extensor surfaces of the elbows and knees and on the scalp. Psoriasis can be exacerbated by trauma, infection, stress and the use of specific systemic medications.
Pityriasis rosea is thought to be caused by a virus, and is characterised by a scaling, pink macular rash that spreads over the trunk and other parts of the body. The condition is self-limiting and usually disappears within 4–6 weeks.
Vitiligo is a benign disorder consisting of irregular patches of skin totally lacking in pigment.
Seborrhoeic dermatitis is a chronic inflammatory condition characterised by dry or moist, red scaly eruptions. Common sites are the scalp, eyelids, face and trunk. The scales have a greasy feel and yellow crusts. Cradle cap is one form of seborrhoeic dermatitis.
HYPERSENSITIVITY DISORDERS
These disorders result from an immediate or delayed reaction after exposure to a certain substance.
Contact dermatitis is caused by an irritant substance that comes into direct contact with the skin, such as detergents, hair dye, metals, preservatives, perfumes or specific fabrics. The resultant inflammation and skin rash may be mild or severe, depending on the individual’s response. Chronic exposure to an irritant may result in the skin becoming reddened, scaly or cracked.
Atopic dermatitis usually occurs when there is a history of asthma and/or hay fever. The condition is characterised by pruritus, redness of the skin, papules and thickening of the skin. Common sites are the face and neck, behind the knees and in the cubital fossae, and on the back of the hands.
Urticaria is a pruritic skin eruption characterised by transient weals with well-defined red margins and pale centres. Urticaria (hives) is most frequently caused by foods, insect bites and inhalants. Specific types of urticaria are associated with systemic diseases. Pruritus associated with urticaria is frequently intense and is commonly accompanied by stinging, numbness or prickling sensations. Urticaria may also be a manifestation of an adverse reaction to a drug, and the skin lesions may appear almost immediately or several days after the drug has been absorbed. Drugs responsible for such adverse reaction include acetylsalicylic acid, penicillin and codeine.
Pemphigus vulgaris is an uncommon disorder of the skin and mucous membranes, characterised by the formation of large bullae containing clear fluid. The disorder is thought to result from an autoimmune response, and may be fatal if untreated. The bullae erupt, ooze and bleed readily, and death is often due to a secondary bacterial infection or loss of blood protein.
TRAUMA
A traumatic injury, which involves damage to the skin, may be due to direct force, penetration or extremes of temperature.
Erythrocyanosis (chilblains) is redness and swelling of the skin as a result of excessive exposure to cold. Burning, itching, blistering and ulceration may occur; the areas most commonly affected are the toes, fingers, nose and ears.
Frostbite is the traumatic effect of extreme cold on the skin and subcutaneous tissues, characterised by pallor of the exposed areas, such as the nose, ears, fingers and toes. Vasoconstriction and damage to blood vessels impair local circulation, resulting in oedema, anoxia and necrosis.
Immersion (trench) foot is a condition of the skin on the feet that develops from continued exposure to wetness and coldness, such as prolonged immersion in cold water. The feet appear pale, cold and swollen, and the individual experiences tingling followed by loss of sensation.
Burns are injuries to the body tissues caused by heat, electricity or chemicals. Thermal burns include injuries caused by flame, steam or hot liquids. Electrical burns result from contact with an electrical current, and chemical burns most often result from contact with caustic substances. A burn may be minor or major, and the degree of local effects and systemic consequences depend on many factors, including the severity of the burn and the age of the individual. (Further information on burns and the care of clients with burns is provided later in this chapter.)
NEOPLASIA
A keloid is a benign overgrowth of fibrous tissue at the site of a wound to the skin. The new tissue is elevated, thickened and reddened. Most keloids flatten and become less noticeable over a period of years. Keloids are more likely to develop if a wound has been infected or if the edges of a wound have been poorly aligned during healing.
Sebaceous cysts are one type of epithelial cyst and consist of a capsule containing a soft yellow–white material. These benign cysts are elevated and firm and range in size from about 0.2–5.0 cm.
A lipoma is a common benign tumour composed of adipose tissue, which is generally encapsulated in the subcutaneous layer of the skin. Lipomas vary in size and most frequently occur on the neck, back, thighs or forearms.
Neurofibromatosis is a congenital condition characterised by numerous neurofibromas of the skin and nerves, by café-au-lait spots on the skin and in some cases by abnormalities of the muscles, bones and internal organs. Many large, pedunculated soft-tissue tumours may develop.
Basal cell carcinoma is a malignant lesion characterised by a shallow ulcer surrounded by a raised well-defined edge. Basal cell carcinomas may also be referred to as rodent ulcers. The most common site is the face, particularly the nose, eyelids and cheeks. Basal cell carcinomas usually occur in people aged over 40 and, as metastasis is rare, the prognosis is favourable.
Squamous cell carcinoma is a malignant lesion characterised by a firm, elevated painless nodule. The most common sites are areas of the body most often exposed to ultraviolet rays. Squamous cell carcinoma is most frequently seen in men over age 55 and, as metastasis is probable, this neoplasm has a higher mortality rate than does basal cell carcinoma.
A melanoma is a malignant tumour that arises from melanocytes. The incidence of melanoma seems to be related to prolonged exposure to the sun, particularly by fair-skinned people. Because metastatic dissemination is relatively common, the mortality rate is high. In its pre-malignant stage, a melanoma appears as a flat, irregularly pigmented macule. Colour changes appear as the melanoma becomes malignant and invasive, with the colour ranging from red, brown and blue to black. Melanoma can occur on any part of the body but most frequently occurs in areas of the skin exposed to sunlight. There are many types of melanoma and, because of its invasive nature, the nodular type is the most serious. Australians have the highest rate of malignant melanoma in the world, and the incidence is particularly high in Queensland and the tropics.
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