The Skin: Anatomy and Physiology


The human body is a wonderful machine. It is more complex, better made and can do more than any machine that man has so far constructed throughout history. The skin is a vital part of this wonderful machine; it is the outer wrapping that protects and holds this human machine in place. The skin is indispensable for human life!

The skin is the largest organ of the human body, and with the exception of the brain, probably is the most complex. The skin of an average adult, if spread out flat, would cover about 18 square feet (1.7 square meters) and it would weigh about six pounds (2.7 kilograms).

With this prosaic covering are millions upon millions of minute structures and mechanisms of surprising intricacy; microscopic oil wells and geysers; waterproofing barriers; disposal units; and reactors sensitive to environmental changes.

The skin is also incredibly alive, continually renewing itself, casting off dead cells that worked incessantly and wear themselves out in the service of their owner. The skin’s connections reach the innermost parts of the body and as a "mirror of the body: it can reflect the status of the body’s health.

Structural Units of the Body

To better understand the complex organ known as the skin, it is important to have some knowledge of the four structural units of the entire organism.

The human body can be described as a large structural unit composed of four kinds of smaller units. The units are the cells, tissues, organs and systems.


The smallest and the most numerous of these units of which the body is composed are the cells.

Many years ago, an English scientist named Robert Hooke looked at a thin cork under his microscope. He saw that the cork was made up of rows and rows of tiny boxes. The boxes resembled the cells of the honeycomb, so he called the boxes cells. The cork that Robert Hooke examined was dried up, and the boxes were hollow, and the walls were all he saw. Today, scientists know that all living things – plants, animals, and the human body are made up of cells. These cells are not hollow, but made up of living material that requires food and oxygen to exist. Cells are the simplest units of living matter and the smallest unit that can maintain life and reproduce itself.

Cells differ in shape, and also, they differ in the work each kind of cell performs within a body. Cells also carry on certain functions that maintain its own life. For example, all cells move substances through their membrane and metabolize food. All but a few types of cells reproduce themselves.

Every cell also performs special functions that help the whole body, for example, muscle cells provide the function of movement, red blood cells transport oxygen, etc.


A group of cells, all of the same kind that performs a particular kind of work, are classified as tissue. For example, groups of cells that transmit impulses back and forth from the brain to other parts of the body make up the nerve tissue. Other kinds of tissue are muscle tissue, connective tissue, supportive tissue, and epithelial tissue. Epithelial tissue forms the outer layer of the skin and the surface of the cavities in the body such as the nose, throat, esophagus, and stomach.


When different kinds of tissue are organized to perform a particular kind of work within the body, the tissues form an organ. For example, the stomach is an organization of muscle, connective, epithelial, and nervous tissues. The muscle and the connective tissue form the walls; epithelial and connective tissue forms the lining; and the nervous tissue extends throughout the wall and lining. Other examples of organs are the heart, liver, lungs, eyes, and tongue. Each of these organs is composed of organized tissue to perform particular work in the body.


Membranes are the special class of organs in that they are merely a thin sheet of tissue, which covers or lines various parts of the body. Of the numerous membranes of the body, four kinds are particularly important: mucous, serous, synovial, and cutaneous.

The mucous membrane lines the cavities or passageways of the body that open to the exterior such as the lining of the mouth and the entire digestive tract, the respiratory passages, and the genito-urinary tract.

The serous and synovial membranes line the cavities of the body, which do not open to the exterior such as the membrane that lines the abdominal cavity, or the thoracic cavity. Synovial membrane lines the joint cavities and tendon sheaths.

The skin and the accessory organs of the skin are made up of cutaneous membrane.


When a number of organs are arranged so that they can perform a particular task for the body it is called a system. There are 10 major systems of the body:

  1. Integumentary
  2. Skeletal
  3. Muscular
  4. Nervous
  5. Endocrine
  6. Circulatory
  7. Respiratory
  8. Digestive
  9. Urinary
  10. Reproductive

These four units of the body – cells, tissues, organs, and the systems – have a relationship of mutual interdependence between the body as a whole and its various parts. Good health of an individual depends on the optimum health of each part, even to the smallest cell. The skin, as the largest organ of the human body, plays an important function in the interdependency of the four units of the human body.

Functions of the Skin

There are five major functions of the skin: protection, temperature regulation, sensory perception, excretion, and vitamin production.


The skin provides the body with an airtight and waterproof covering that holds the units of the body in. When unbroken, the skin acts as a barrier to harmful bacteria. The pigment of the color matter, melanin, of the skin screens out certain harmful rays of the sun. The skin minimizes the mechanical injury of underlying structures.

Temperature Regulation

The skin helps the body t regulate its own temperature. When the body surface is cold, blood vessels in the skin contract and force the blood deeper into the body. This prevents the body from losing much heat by radiation. When the body is too warm, the same blood vessels expand and bring more blood to the surface of the skin. This allows the body to lose heat by radiation. Also, the sweat glands pour out perspiration. The perspiration evaporates and since evaporation is a cooling process, the skin is further cooled.

Sensory Perception

Millions of microscopic nerve endings are distributed throughout the skin. These serve as receptors for pain, touch, heat, pressure, position, etc. They are the body’s antennae, keeping it informed of changes in the environment. Within this context the skin functions as a "sex organ."


Sweat is mainly water. Only about one half of one percent consists of other chemicals. They include a small amount of sodium chloride, urea, and lactic acid.

Vitamin Production

Vitamin D, an essential vitamin, is formed in the body by exposure of the skin to ultraviolet rays, either from the sun or a lamp. After being produced or on the skin, vitamin D is absorbed through the skin and carried to the liver and other organs for us.

Structure of the Skin

Anatomically, the skin is a layered organ. There are two basic layers to the skin: the outer and the thinner layer called the epidermis, and the inner, thicker layer called the dermis. The word "dermis" is taken from the original Greek work for skin. The Greek word "epi," meaning "over," is added to the word "dermis" to form the word "epidermis" for the outer layer of the skin.


The outer skin, epidermis, is made up of numerous cells that are placed side-by-side and arranged one above the other in several layers. The topmost layer (stratum corneum) is composed of dead cells that are continually being worn off. Unlike reptiles that shed their skin all at once, humans shed skin as thin flakes. These flakes are the dead skin that a person often rubs off with a towel after taking a bath or peels off as skin patches after a sunburn. When the skin is exposed to repeated pressure, the dead cells clump together instead of falling off, and a callus or a "corn" is formed. Dandruff is a name given to dead skin cells that have flaked off from the scalp in large amounts. New cells originate in the germinative layer at the bottom of the epidermis. These new cells mature as they move upward in the layers of the epidermis; they become flatter and drier as they are pushed upward and outward by the new cells below them. It takes about a month for every skin cell to die and be replaced.

There are some nerve cells in the epidermis, but there are no blood vessels. The epidermis contains the pigment (granules of material called melanin) that is responsible for the color of our skin, suntan, and freckles.

The Dermis

The dermis, the inner and thicker layer of the skin, lies beneath the epidermis. It is also known as the corium or the "true skin." The surface or upper layer of this dermis is cobbled, ridged, valleyed, and meshes with the pitted undersurface of the epidermis and binds the two together. These ridges are arranged in regular curved rows and are as unique to each individual person as fingerprints. However, these ridges have a more fundamental function. Ducts of sweat glands surface through these ridges to give a nonskid surface to hands and feet and enable us to pick up small objects and do delicate manipulations. Into this upper layer of the dermis come thousands of capillaries, the small blood vessels that bring food and oxygen to the cells and remove waste. This inner layer is strong and elastic, and it contains nerve fibers; receptor organs for sensations of touch, pain, heat and cold, muscular elements, hair follicles, and oil and sweat glands.

Deeper in the dermis are the roots of skin glands and hair, as well as, more blood and lymph vessels, more nerves and larger and tougher fibers.

Accessory Organs of the Skin

The accessory organs of the skin are the skin glands, the hair, and the nails.

The Skin Glands

There are two kinds of skin glands; ones that pour out sweat and others that secrete oil.

The Sweat Glands

The sweat glands are the most common ad they are found all over the body. There are about two million sweat glands distributed over the body surface. The most numerous are found on the forehead, face, palms, soles, the groin and the armpits. The sweat gland is a small, tight coil of cells in contacts with a network of capillaries, the smallest blood vessel. Ducts of the gland corkscrew through the epidermis to the skin surface. These glands give off a small amount of waste material, but their most important function is to regulate body heat. As the sweat evaporates, it cools the surface of the body.

The Sebaceous Glands

The second group of skin glands are the sebaceous glands. These glands produce oils and fats and are about as numerous as the sweat glands. These glands generally open into the hair follicle and give off an oily substance called sebum. This sebum seeps into the hair follicle and works its way to the surface where it spreads a thin film. Its primary function is lubrication for the hairshaft and the horny layers of the skin. The lubricant also helps prevent excessive evaporation and absorption of water and excess heat loss.

When a hard fatty material from an oil gland blocks the skin opening, it forms a blackhead.

In addition, the chemicals in sebum play an important role in maintaining the normal acidity (PH) of the skin. This oil or sebum keeps the skin soft and pliant. It protects the body from water absorption through the skin and excessive evaporation from the skin. Because fat is a poor conductor of heat, the sebum lessens the amount of heat loss from the body’s surface.

The surface of the normal healthy skin is slightly acid in reaction. A change toward alkalinity is thought to increase the susceptibility of skin to fungal infection and other disorders.

Oil glands are distributed almost over the entire body and are the largest in regions of the forehead, face, neck, and chest. However, the palms of the hands and the soles of the feet are poorly greased. That is the reason why the skin in the inner hand becomes wrinkled and white if immersed in water for some time.

Another type of gland is found in the lining of the external ear canal and it secretes a thick wax called cerumen. Its function is to protect the tissues of the middle ear.


The structure of the hair is similar to that of the outer layer of skin. Just as the epidermis is formed by the cells in its deepest layer, reproducing and pushing the cells which become horny in character, so a hair is developed by pushing a group of cells at its base, pushing upward and in the process becoming keratinized. The part of the hair that is visible is the shaft, whereas that which is embedded in the dermis is the root. The root, together with its covering, forms the hair follicle. At the bottom of the hair follicle is a loop of capillaries enclosed in a connective tissue covering called the hair papilla. The cluster of epithelial cells lying over the papilla are the ones that reproduced and eventually form the hair shaft. As long as these cells remain alive, hair will regenerate even though it will be cut or plucked or otherwise removed.

Each hair is kept soft and pliable by two or more sebaceous glands that secrete varying amounts of oily sebum into the follicle near the surface of the skin. Attached to the follicle, too, are small bundles known as arrector pile muscles. These muscles are of interest because when they contract, the hair "stands on end," as it does in extreme fright or cold. This mechanism also produces "gooseflesh." Goosepimples is the raised skin produced by hair in upright position.

Hair color is due to different amounts of melanin pigments in the outer layer or cortex of the hair. White hair contains little or no melanin.

The hair around the eyes and in the nose functions as a protective mechanism to keep out dust and foreign matter.

Some Common Skin Problems Are:

  • Acne – an accumulation of pimples over the face and neck area.
  • Blackheads – pores that are filled with an accumulation of oil and dirt.
  • Boils – a boil is the result of the same bacteria that causes pimples spreading through the layers of the skin. They destroy tissue and cause an accumulation of puss.
  • Cold Sores – fever blisters caused by a virus and an accumulation of fluid between the layers of the skin with scales erupting on the surface.
  • Exzema – a reaction of the skin to allergies or emotional upsets, recognized by red swollen scaly areas which discharge a clear fluid.
  • Freckles – patches or spots of thick pigment of the skin. Sunlight increasing freckling.
  • Hives – a raised area of skin with a clear fluid underneath caused by many different irritants.
  • Moles – brown moles are an overgrowth of epidermis and pigment. They are considered harmless if they aren’t in a place where they are irritated. Black moles are dangerous and may become cancerous.
  • Pimples – result from bacteria in a pore or around a hair follicle.
  • Psoriasis – patches of raised red skin with silvery scales. The cause is generally unknown but could be emotional.
  • Warts – believed to be caused by a virus, they are horny, raised outgrowths of the epidermis.

Direct Skin Factors Causing Skin Breakdown

There are many factors which contribute to the breakdown of the skin, but some of the most common causes are ischemia, incontinence of urine and feces, sweating and exposure of the skin to digestive juices.


Ischemia is a condition in which the amount or quality of blood delivered to the tissues is insufficient to supply nourishment and oxygen to that area. Bedsores or decubill is one of the most persistent problems resulting from localized area of ischemia. Predisposing factors to the development of this problem include pressure on the skin, especially on the bony prominences; immobilization; poor nutrition; lack of sensory nerve supply and edema or swelling of the tissue.

When the weight of the body exerts pressure on the skin tissue, the skin and subcutaneous tissue are compressed against the bony prominence. Approximately seven pounds of pressure per square inch of surface on the tissue is sufficient to shut off blood supply. Tissue can be destroyed in as little as thirty minutes.

When a person lies on his back, the areas of the greatest pressure are the shoulders, sacrum and heels. The person lying on his side bears pressure on the shoulder, hip, knees, and ankles. The back of the head of infants is frequently a site for pressure sores, and in other cases, in the absence of a pillow, the weight of the head is often concentrated on the ear.

Many areas of the body are normally protected by fat pads, but atrophy of muscle and fat contribute to the possibility of pressure sores.

The most successful treatment of bedsores is prevention. The first step is to identify conditions that create pressure areas or obstructions which may undersupply blood to the tissue. Other measures include mobilization, and keeping the skin clean, dry and lubricated, also, special attention should be given to the feet since poor circulation, from lack of activity, causes the skin to become dry and the nails to harden and become horny.


A direct factor causing skin breakdown is continued exposure of the skin to urine. Urea contained in urine is decomposed by bacteria to ammonia, a highly irritating substance. The skin does not tolerate being wet for long periods of time; and, the wetness destroys the natural barriers for the skin’s protection against destructive agents such as urine.

Prevention of irritation depends n the measures taken to prevent the urine from coming into contact with the skin. Two important measures are washing and drying the exposed areas of the skin, and keeping the linen or clothing next to the skin dry. Special attention should be given to the perineal area and the scrotum, and to the abdominal folds of the skin in obese persons.


The digestive tract is an open-ended muscle tube which passes through the body. The tube is more than thirty (30) feet long from one open end to the other. Digestion is a process of continuous chemical simplification of material that enters the mouth. This material is split into fragments and can be absorbed through the walls of this tube. As this material passes on its way, it is mixed with digestive enzymes.

The feces is the contents of a bowel movement: the stool. Feces is more than unabsorbed food residues. The greatest pat of the solid matter is made up of materials excreted from blood and cells shed by lining membranes of the intestines. About ten (10) percent of this solid matter is bacteria. Practically all of the protein, fat and carbohydrate that is eaten is absorbed. Unabsorbed food residue consist largely of indigestible vegetable cellulose. This indigestible "roughage" stimulates activity and secretions of the bowel. If the bowel is stimulated more then normal, the fluids are not absorbed and the result is diarrhea. It is the moisture and the bacteria of the feces that are the causative agents contributing to skin breakdown and infection.

Washing and drying and lubricating the skin is essential in the prevention of decubitus and infection caused by incontinence of feces.


The moisture of sweat and the chemicals in the sweat are contributing factors in skin breakdown. When the sweat is not able to evaporate, or is contained by clothing, it creates an irritation called heat rash. Many persons get this rash under arms, chin, crotch, or in other fold of the skin where this moisture is contained. Bacteria, yeasts and molds grow and destroy the normal defenses of the skin. Scratching of the skin further complicates the condition by breaking down the natural defense the skin to bacteria.

Digestive Juices

Digestive juices, when they escape from the gastrointestinal tract, also are capable of causing skin breakdown. These digestive juices contain protein-splitting enzymes. These enzymes disrupt the structure of the cell by breaking down the protein construction of the cells into polypeptides or amino acids.

In cases where abnormal opening, such as an ileostomy or colostomy, allow the intestinal content to make contact with the skin, the area around the opening is prone to skin breakdown. The situation is more acute when the feces is fluid rather than solid matter: the watery state brings the enzymes in contact with the skin.

Proper application of ileostomy and colostomy appliances and continued good skin care are preventative measures to avoid irritation of the skin around the stoma.

Other Factors Which Affect The Skin

Differences In Skin Due to Sex

Most human bodies are very alike and the differences are usually minor. The skin is no exception. The greatest difference is attributed to sex and the following observations have been made:

  • Chemicals from the male glands increase the thickness of the skin and strengthen the tissues of the dermis.
  • The skin of men is hairier and somewhat coarser than that of women.
  • Men have more sweat glands since men are larger and have more skin.
  • Male skin cells have a somewhat deeper color due to the greater amount of melanin in the skin.
  • Men have greater output of sebaceous glands.
  • The chemicals from the female sex glands make skin softer.
  • Women have fewer and shorter body hairs, but the hair on their head is finer and grows longer.

Many men lose hair and women may grow hair. Some hair grows gray or white and becomes more sparse.

Race has very little effect on people’s skin, and, may indicate only a slight variation in the distribution of skin glands. Dark color is due to specific skin cells and these cells exist in about the same quantity in all people. In some groups of people, the cells are larger or produce more melanin.

Other skin conditions are inherited such as the color of the hair and the fairness of the skin.


Age does have a distinct effect on the skin. At birth a baby’s skin is reddish in color and soon becomes pink. The skin begins to develop in about a month after birth. The temperature mechanism is weak and the infant requires protection from strong sunlight.

With age, the elasticity of the skin decreases and so does the underlying fat. After forty years, the skin begins to get thinner, dryer and darker.

As age progresses, there is a tendency toward dryness and cracking of the horny layer of the skin. The color may be yellowish with a sallow grayish hue. Often these are areas of discoloration and scaling. The fine wrinkles which appear are the result of atrophy of the dermal papillae and the flattening of the epithelium. Nails are also affected by age; the rate of growth of nails diminishes and they may become coarse and thick, or thin and brittle.

Older persons are subject to the same skin diseases as the young adult, but several conditionals including pruritus occur frequently.


Weather conditions affect the skin in so far as the reaction of the skin’s surface can vary from season to season due to variations in temperature and humidity.

Dry hot summer days tend to dry out the surface of the skin. In a similar manner, the dry heated air of a cold home in winter will produce the same effect.

Moisture, too, affects the skin. Excess humidity prevents the surface evaporation of sweat. This can result in a feeling of extreme discomfort, even though the ambient temperature may not be excessively high. A resulting buildup of sweat by products may produce skin rash and irritation.


Although the skin is a barrier, certain chemicals, natural and man-made can affect the skin. Many people are sensitive to the sap, leaves, and roots of plants which can result in swelling, rash and blisters of the skin. Plant and animal products carried by the wind or in food, affect people and can show up as rashes and irritations on the skin. Pesticides and many chemicals, including detergents at home can cause an inflammation of the skin. The skin also has the capability to absorb fatal amounts of toxic substances.

Infectious Diseases

A number of diseases also cause swelling of the skin, rashes, inflammation, and blisters. For example, the most common disease among children that cause swelling or rashes are measles, mumps, and chicken pox.

Skin Breakdown – General


For centuries, health care professionals have recognized that skin care is an essential component of the medical regimen of the sick, chronically ill, and the disabled. Equally as long, they have struggled to keep the skin of patients intact and free of abrasions and breakdown. Despite the advances in medical technology and pharmacology, skin care and the treatment of skin breakdown continues to be a challenge and a problem for today’s health care providers.

Terms Commonly Used to Describe the Conditions of the Skin

Attempts to classify various forms of skin breakdown has brought terms into usage. However, there is no standard vocabulary which meaningfully defines the degree of skin destruction or injury. The terms listed are those which are commonly used by health care providers in describing the condition of the skin and the degree of skin breakdown.

  • Intact – skin is unbroken.
  • Contusion – an injury in which the skin is not broken.
  • Excoriation – the removal of an area of skin; a raw area.
  • Wound – a break in the continuity of a tissue of the body, either external or internal. Wounds are classified as open or closed. An open wound is a break in the skin or mucous membrane. A closed wound involved the underlying tissues without a break in the skin or mucous membrane.
  • Abrasion – a spot rubbed bare of mucous membrane or skin, and thereby damaged. Bleeding in an abrasion is usually limited to oozing of blood from ruptured small veins and capillaries. However, there is danger of contamination and infection, or further breakdown, depending on the environment.
  • Friction – the resistance when two surfaces slide against each other. Friction will destroy epithelial tissue.
  • Burn – an injury that results from heat (direct or by friction), chemical agents, or radiation. It may vary in depth, size, and severity, and may damage cells in the affected area.
  • First Degree Burns – signs of redness or skin discoloration, mild swelling, and pain. Healing occurs rapidly.
  • Second Degree Burns – signs are deeper skin discoloration and appear mottles with blister formations. There is swelling, and usually some loss of plasma through the damaged layer of skin. Second degree burns are more painful than third degree burns, since in the third degree burns the nerve endings in the skin are destroyed.
  • Third Degree Burns – signs involve deeper destruction, the burn will look white and charred. There is coagulation of red blood cells and the destruction of the skin.
  • Frostbite – results when crystals from wither superficially or deeply in the fluids underlying the soft tissues of the skin. The extent of injury depends upon the depth of the involvement.
  • Flush – a deep red color, as in blush. It is usually associated with an elevated temperature.
  • Cyanosis – a dusky, bluish color usually seen on the lips and on the nail beds; it is caused by lack of oxygen.
  • Rash – an eruption on the skin surface, varying in size and elevation, color and type of spots, depending on the cause.
  • Ecchymosis – discoloration due to escape of blood into the tissue, lay term (black and blue).
  • Edema – retention of fluid in the tissue with consequent swelling.
  • Drainage – a systematic withdrawal of fluids and discharge from a wound, sore, or cavity.
  • Serious Drainage – fluids containing only the clear portion of the blood.
  • Sanguineous – drainage of fluids containing a great deal of blood.
  • Serosanguineous – drainage of fluids containing both serum and blood.
  • Ischemia – local and temporary deficiency of blood due to interruptions of the blood supply to the part.
  • Blanched – white and pale color of the skin.
  • Maceration – softening of the skin by soaking; or mechanically as in the removal of adhesives, appliances and other devices.
  • Hyperemia – congestion.


Hypoproteinemia is the lack of sufficient protein to maintain the rate of cell replacement. Proteins are part of the structure of all body fluids except bile and urine. Cells are constantly disintegrating and new ones are replacing them. Proteins are, next to water, the chief constituents of the body cells. In order for this nutrient to be made available to the body, the daily intake of protein must be adequate or hypoproteinemia will develop.


Whenever cells are damaged by any kind of agent they release a substance called histamine into the fluid which surrounds the cells (intracellular). This causes a reaction that is commonly referred to as an inflammation. This reaction is the body’s way to surround the damaged area and act as a line of defense to any bacteria which may have been introduced by the damage. The histamine also acts on the small blood vessels to release blood cells and blood serum to the surrounding tissue. This increase in the amount of blood causes the part to become red, hot, and swollen. When the area becomes swollen, the nerve endings are compressed and the area becomes painful. If the swelling continues to increase, it can produce loss of function of that part. Redness, swelling, heat and pain are the body’s symptoms of inflammation.

Prevention of skin breakdown in areas where inflammation occurs depends on providing adequate circulation of blood to and from those tissues. This circulation provides nutrients and white blood cells to the area and also removes the waste products which are formed as a result of this inflammation, some form of moist or dry heat is applied to the area as a way to localize infection.

When skin breakdown occurs as the result of an inflammation and skin tissue is destroyed, repair of that tissue is dependent on the process called regeneration. Nutritional status and age are important factors in cell regeneration.

The body makes every attempt to restore tissue damage. If the area is tissue damage is slight, the body regenerates the tissue with little sign of injury. If the tissue damage is extensive, the body fills the gap with connective tissue or a scar, which holds the gap together.

The health care provider’s main function in treating an inflammatory process is to assist the body to deal with the inflammation and to provide an optimum environment which will assists the skin to replace the cells which have been destroyed.


Man lives in a world populated with many forms of life, some of which threaten his existence. Many of these forms of life are not directly visible although their effect can be observed. A class of these invisible forms of life are microbes, commonly called germs. There are "good" microbes as well as "bad" ones. In fact, the good ones far outnumber the bad ones. Many of these microbes are in or on our bodies and they are harmless and coexists with each other. Many microbes are essential and useful such as those which inhabit the intestinal tract.

Those germs which produce disease are called pathogens. These pathogens get into the body in many ways. They may be passed from person to person; they may be swallowed in food and drink or inhaled; or be acquired by contact with contaminated materials or objects. Also, these pathogens can be injected through an insect bite, or they can penetrate the skin through a wound or scratch.

The term infection indicates that a pathogen is present and that it is multiplying. Some of the disease-producing organisms are bacteria, viruses, parasites and fungi.

Bacteria are the disease-producing organisms which are a common contributing factor in skin breakdown and tissue destruction.

Bacteria are one-celled microorganisms of the plant kingdom. They are the smallest living thing which has its own self-contained metabolic processes. Each bacteria have an outer covering called a cell membrane which encloses a chemical process as complicated as within any cell of the human body.

There are many strains and families of bacteria. Some require oxygen in order to grow and these are aerobic. Others will not grow if oxygen is present and these are anerobic. Some bacteria have whip like tails which enable them to move freely. Some bacteria grow at low temperature, others grow only in near or at body temperature. Factors which help bacteria grow are heat, humidity and some media which the bacteria use as food.

The skin functions as a first line of defense against these pathogens. Normal, healthy skin is an effective barrier in preventing bacteria from entering the body. The normal acid secretion of the skin (pH 5.5) tends to inhibit the growth of bacteria. Bacteria that are normally present on the skin are usually non-pathogenic. Most staphylococci are the exception. If the skin is not broken, and its glands excrete normally, pathogenic bacteria cannot enter the body through the skin to produce disease. Bacteria, however, are present on the skin in great number and penetrate the hair follicles and the glands. Because perspiration continually brings bacteria out into the skin, cleansing with soap and water removes the surface bacteria, but it does not remove all bacteria. The skin is never considered sterile or free from organisms. For this reason, for example, the hands of a surgeon are thoroughly scrubbed and the surgeon wears gloves to prevent introducing bacteria into the wound when performing a surgical procedure. The additional precaution of cleansing the skin of the patient and of using sterile instruments minimize the surgical incision through the skin is made.

After any trauma to the skin, whether it’s caused by an accident or surgical procedure, there can be additional sources of contamination and irritation of the skin. These sources can be feces; contaminated urine; secretion from other open areas of the body; or fluids from an infection or an abscess. When body tissue is invaded by bacteria a local reaction called inflammation occurs. This inflammation is a reaction caused by the body’s attempt to localize the invading bacteria. There is first an increase in blood flow to the site and a dilatation of the capillaries. The dilatation is thought to be caused by a histamine-like substance which is expelled by the tissue under attack. The increase blood brings white blood cells to the area. However, the bacteria and their toxins may be virulent enough to destroy many white blood cells before they are themselves destroyed. This may result in a local accumulation of pus. The bacteria most commonly causing reactions are staphylococci found on the skin and the strephlococci normally found in the mouth and nose.

Health care providers recognize that any procedure that causes a break in a barrier between external and internal body environment (skin or mucous membrane) deprives the person of one of the defenses against infection. Many procedures, which include instrumentation, such as inserting a catheter, intravenous infusions, injections, or drainage from body cavities, provide a port of entry for bacteria. In addition, treatment with chemicals or physical agents may lower the resistance of a person against bacteria and contribute to tissue destruction.

Control of skin infections is a modern triumph of the science and technology in medicine. Existing chemotherapeutic agents are powerful weapons to fight bacteria. But, the health care providers know that infections still occur and should not be neglected just because there is a drug to treat it. They also know that many infections are preventable with good hygienic measures; especially the use of cleansing agents and water. They also are aware that contamination is still the most common method of introducing or spreading bacteria.

Chemical Responses

There are several factors that have contributed to man’s survival, one being his innate defense posture in response to physical danger. In a similar manner, man has survived the threats of disease and injury by the body’s ability to internally produce chemicals that are necessary for survival.

These internal reactions are often reflected by changes in the normal skin. There are several reasons for these changes but the most common include reaction to infections, reaction to ingestion of toxic substances, allergic reactions to internal and external substances, and exposure of the skin to toxic substances.

The most common body response to the above mentioned causative agents is inflammation, the body’s natural response to injury of the cells. This response involves the blood vessels, the fluid and cells surrounding the area of injury or disease. This is a useful response because it serves to destroy or neutralize the cause of injury and prepares the skin for regeneration. Some of the physical causes that induce inflammation are heat, cold radiant rays (including ultraviolet, infrared, and radio active).

Chemical agents also act as irritants to the skin any body and produce inflammation. They may be extrinsic or intrinsic irritants. Examples of extrinsic chemical irritants to the skin include strong acids and bases, insect bites, allergies, and the toxins produced by microorganisms. The chemical irritants of intrinsic origin are substances that are produces in the body. They may be normal substances such as pancreatic juices that escape in the gastrointestinal tract and come in contact with tissues not protected from the digesting enzymes. Large areas of the skin breakdown can occur when a fistula tract drains the secretion to the surface of the body. This is called an enterocutareous fistula. An ostomy pouch can be utilized to control the output and prevent skin breakdown.

Blood is another normal body fluid that produces an inflammatory reaction in the tissue. When the blood infiltrates tissue as a result of a break or rupture in a blood vessel, soreness and redness occur. An example, is the rupture of a small blood vessel by injection with a needle.

Products of metabolism may also act as an irritant. In gout, because of a defect in metabolism of purines, uric acid crystals accumulate in tissues about joints and cause inflammation and redness of the skin. Among other causes of inflammation are antigens – antibody reaction to allergens. The antigen is the substance to which the body reacts. An antibody is a protein molecule that the antigen stimulates the body to manufacture. There are thousands of antigens chiefly in foods, dusts, pollens, medicines and other chemicals.

Exactly how chemical substances are freed from the cells that contain them is not clear. Of these substances, histamine is familiar to the public. But other chemicals are also involved. Histamine plays an important role in the visible reaction on the skin. It dilates the blood vessels, causes local swelling, and a raised area called a "wheal." Wheals on the skin are called "hives." These wheals can occur in other organs of the body and can produce extensive swelling with serious results. Hives of the skin usually produce mild burning pain and itching; and they can become extensive and intolerable. The complications associated with itching is the possible contamination of the area caused by scratching to relieve the itching. Topical applications of medication is usually prescribed for relief of pain and itching and for protection of the skin.

Contactants are also irritants to the skin which can produce inflammation and skin breakdown. Acids, strong alkalies and other dyes and materials may cause trouble the first time the skin comes in contact with them. No one is immune to them and true allergy is not usually involved. Contact allergens are materials that are harmless to most people, but produce allergic symptoms in sensitive skin. All plants can cause contact inflammation and new offenders are reported almost daily.

Prevention of Skin Breakdown

Most health care providers agree that the best treatment of skin breakdown is prevention. The two most important objectives in preventing skin breakdown are: identifying the factors and conditions that contribute to skin breakdown; and, in developing and implementing a plan to maintain and improve the condition of the skin.

The factors contributing to skin breakdown have been described. The following are measures that must be incorporated in a nursing care plan to provide optimal skin care.

The health care professionals and other skin care specialists are guided by four general principles in planning or giving skin care. These principles are based on the assumption that:

  • Resistance to injury of the skin and the mucous membrane varies among individuals
  • Adequate circulation is necessary to maintain life of the skin.
  • Skin cells that are nourished and hydrated are more resistant to trauma and disease.
  • Unbroken and healthy skin and mucous membrane serve as a first line defense against harmful agents.

Based on these principles, the objective of providing skin care is to maintain the skin at its highest level of wellness.

Skin Hygiene

Bathe with mild soap, rinse and dry thoroughly with soft towels. Keep local areas of skin clean, dry and free of body waste materials such as urine, perspiration, feces, and wound drainage. Lubricate the skin with lotion to keep it soft and pliable; giving special attention to weight bearing prominences covered only by skin and small amounts of subcutaneous tissue. Inspect skin frequently for signs and symptoms of skin breakdown. Recognize those persons in whom skin breakdown is likely to develop and provide nursing support systems to prevent damage to the skin.

Relieve Pressure

Encourage persons to be active and move frequently to shift weight. Position body with pillows and other support devices. Utilize water or air flotation mattresses and other mechanical devices for turning and suspension. Keep foundation sheets dry and stretched to avoid wrinkles. Employ active and passive exercise to improve muscular tone and circulation.

Improve Circulation

Massage and stroke lightly around bony prominences to promote venous return, reduce edema and improve vascular tone.

Avoid Shearing Force

Use good transfer techniques to reduce friction and resulting loss of epidermis. Provide heel and elbow protectors. Lift rather than pill persons requiring repositioning or transfer.

Avoid Friction

Provide padding for casts, braces and splints, and compressing bandages. Apply skin barriers before applying adhesives. Secure appliances and dressings properly. Lubricate skin to protect from irritation and chaffing.

Provide Nutrition

Improve nutritional status by providing a high protein diet, vitamin and protein supplements, and iron preparations. Monitor hemoglobin, hematocrit and protein levels by laboratory procedures.

The Treatment of Skin Breakdown

The objectives of the treatment for skin breakdown are to remove irritants, relieve pressure, to assist healing by increasing the circulation to the affected area, and to prevent further destruction of tissue.

The treatment varies with the condition of the skin and the amount of destruction already present. Preventive measures, as listed previously in this section, are started and/or continued.

Mechanical cleansing of the area is often part of the medical regimen since this procedure helps to clear up sepsis and stimulates regeneration of the epithelial layer of the skin.

Physical modalities are often prescribes in the treatment of skin breakdown; the areas are exposed to sunlight, air or other drying agents. Whirlpool treatments are often used to increase circulation and to act as a debriding action. Some medical regimen including oxygen under pressure (hyperbaric oxygenation) applied directly to the open area. This procedure directs more oxygen to the tissues, and supposedly, hastens the metabolic action in regenerating new cells.

Other modalities include the use of topical applications that act as skin barriers, drying agents, and antiseptics. Sprays containing antibiotics and corticosteroids are also popular topical medications used in preventing or treating infections associated with skin breakdown.

Local applications of enzyme preparations are used to digest dead tissue or purulent drainage.

Good nutrition is essential in the treatment of skin breakdown and the medical regimen usually includes a balanced diet with additional high protein feedings, iron, and vitamin C supplements. Deficiency of protein is usually associated with skin breakdown where a large amount of drainage is present.


As you have learned, the skin is a complex organ of the body and interdependent of the other systems of the body to function properly and effectively. It is also dependent on its internal and external environment to keep it intact and healthy.

In this chapter you have become aware of the basic principles of skin care and skin breakdown. Health care professionals universally recognize and utilize these principles in the daily care of the skin.

In order to prevent and treat skin breakdown most effectively, a careful analysis of the skin and the patient must precede treatment. Hopefully, with the material provided and the products available, better and more effective skin care is an attainable goal.

Care-Tech Laboratories, Inc.
3224 Kingshighway Blvd. St. Louis, Missouri 63139
Phone (314) 772-4610 / Fax (314) 772-4613 / Toll-free (800) 325-9681
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