Chapter 18 The Integumentary System

5.4 Diseases, Disorders, and Injuries of the Integumentary System

Learning Objectives

By the finish of this department, you will exist able to:

Discuss several mutual diseases, disorders, and injuries that impact the integumentary arrangement

Describe several different diseases and disorders of the skin
Depict the outcome of injury to the skin and the process of healing

The integumentary organization is susceptible to a multifariousness of diseases, disorders, and injuries. These range from annoying but relatively beneficial bacterial or fungal infections that are categorized every bit disorders, to skin cancer and severe burns, which can exist fatal. In this department, y'all volition acquire several of the virtually common pare conditions.

Diseases

One of the most talked about diseases is skin cancer. Cancer is a broad term that describes diseases caused past abnormal cells in the torso dividing uncontrollably. Nearly cancers are identified by the organ or tissue in which the cancer originates. One common form of cancer is peel cancer. The Skin Cancer Foundation reports that i in five Americans volition experience some type of skin cancer in their lifetime. The degradation of the ozone layer in the temper and the resulting increment in exposure to UV radiation has contributed to its rise. Overexposure to UV radiations damages Deoxyribonucleic acid, which can lead to the germination of malignant lesions. Although melanin offers some protection against DNA damage from the sun, often information technology is not enough. The fact that cancers can as well occur on areas of the trunk that are normally non exposed to UV radiation suggests that there are additional factors that can pb to cancerous lesions.

In general, cancers outcome from an aggregating of Dna mutations. These mutations tin can effect in cell populations that do not die when they should and uncontrolled jail cell proliferation that leads to tumors. Although many tumors are beneficial (harmless), some produce cells that can mobilize and plant tumors in other organs of the body; this procedure is referred to as metastasis. Cancers are characterized by their ability to metastasize.

Basal Prison cell Carcinoma

Basal cell carcinoma is a form of cancer that affects the mitotically agile stem cells in the stratum basale of the epidermis. Information technology is the about common of all cancers that occur in the U.s. and is ofttimes found on the head, neck, arms, and dorsum, which are areas that are virtually susceptible to long-term sun exposure. Although UV rays are the main culprit, exposure to other agents, such as radiation and arsenic, can besides lead to this type of cancer. Wounds on the pare due to open sores, tattoos, burns, etc. may exist predisposing factors also. Basal jail cell carcinomas start in the stratum basale and usually spread forth this boundary. At some indicate, they begin to abound toward the surface and go an uneven patch, bump, growth, or scar on the skin surface (Effigy 5.four.1). Similar most cancers, basal cell carcinomas respond best to treatment when defenseless early. Treatment options include surgery, freezing (cryosurgery), and topical ointments (Mayo Clinic 2012).

This photo shows an enlarged view of a basal cell carcinoma, a large, pink, irregular bump on the skin. The carcinoma is marked with irregular, dark-red stripes that resemble tiny blood vessels. The surrounding skin is the same pink color as the carcinoma, but without the red striping or raised appearance — **Figure 5.iv.1** – **Basal Jail cell Carcinoma:** Basal jail cell carcinoma can take several dissimilar forms. Similar to other forms of skin cancer, it is readily cured if caught early on and treated. (credit: John Hendrix, MD)

Squamous Jail cell Carcinoma

Squamous prison cell carcinoma is a cancer that affects the keratinocytes of the stratum spinosum and presents every bit lesions commonly constitute on the scalp, ears, and hands (Figure 5.4.2). It is the 2d most common skin cancer. The American Cancer Social club reports that ii of 10 skin cancers are squamous cell carcinomas, and it is more than ambitious than basal cell carcinoma. If non removed, these carcinomas can metastasize. Surgery and radiation are used to cure squamous cell carcinoma.

This photo shows a man's nose. The squamous cell carcinoma is located just above the tip of the nose and appears as a deep red, irregularly-shaped sore that spans almost the entire bridge of his nose. — **Figure v.iv.ii** – **Squamous Cell Carcinoma:** Squamous cell carcinoma presents here equally a lesion on an individual's nose. (credit: the National Cancer Institute)

Melanoma

A melanoma is a cancer characterized by the uncontrolled growth of melanocytes, the pigment-producing cells in the epidermis. Typically, a melanoma develops from a mole. It is the most fatal of all pare cancers, as information technology is highly metastatic and can exist difficult to notice before information technology has spread to other organs. Melanomas usually appear every bit asymmetrical brownish and black patches with uneven borders and a raised surface (Figure 5.iv.three). Treatment typically involves surgical excision and immunotherapy.

Doctors ofttimes give their patients the following ABCDE mnemonic to help with the diagnosis of early-phase melanoma. If y'all observe a mole on your torso displaying these signs, consult a doctor.

Asymmetry – the two sides are not symmetrical
Borders – the edges are irregular in shape
Color – the color is varied shades of chocolate-brown or blackness
Diameter – information technology is larger than half dozen mm (0.24 in)
Eastvolving – its shape has changed

Some specialists cite the post-obit additional signs for the nigh serious form, nodular melanoma:

Elevated – information technology is raised on the skin surface
Firm – it feels hard to the touch
Thourowing – information technology is getting larger

Skin Disorders

Two common skin disorders are eczema and acne. Eczema is an inflammatory status and occurs in individuals of all ages. Acne involves the clogging of pores, which tin can lead to infection and inflammation, and is ofttimes seen in adolescents. Other disorders, not discussed here, include seborrheic dermatitis (on the scalp), psoriasis, cold sores, impetigo, scabies, hives, and warts.

Eczema

Eczema is an allergic reaction that manifests as dry, itchy patches of skin that resemble rashes (Effigy 5.4.4). It may be accompanied past swelling of the pare, flaking, and in severe cases, haemorrhage. Symptoms are unremarkably managed with moisturizers, corticosteroid creams, and immunosuppressants.

Acne

Acne is a skin disturbance that typically occurs on areas of the skin that are rich in sebaceous glands (oil glands), such every bit the face and back. It is almost common along with the onset of puberty due to associated hormonal changes, but can also occur in infants and continue into machismo. Hormones, such as androgens, stimulate the release of sebum. Pilus follicles become blocked due to an overproduction and accumulation of sebum and keratin. This plug is initially white, known equally a whitehead. The sebum, when oxidized by exposure to air, turns black, known as a blackhead. Acne results from infection past acne-causing bacteria (Propionibacterium and Staphylococcus), which can lead to redness in light skinned individuals and hyperpigmentation in darker skinned individuals. Severe acne can potentially lead to scarring due to the natural wound healing process (Effigy 5.four.v).

Career Connection

Dermatologist
Have you ever had a skin rash that did not respond to over-the-counter creams, or a mole that yous were concerned nearly? Dermatologists help patients with these types of problems and more, on a daily basis. Dermatologists are medical doctors who specialize in diagnosing and treating pare disorders. Like all medical doctors, dermatologists earn a medical caste and then complete several years of residency training. In addition, dermatologists may then participate in a dermatology fellowship or complete additional, specialized grooming in a dermatology exercise. If practicing in the United States, dermatologists must pass the United States Medical Licensing Exam (USMLE), become licensed in their state of practice, and be certified by the American Board of Dermatology.

Nigh dermatologists work in a medical office or private-do setting. They diagnose skin conditions and rashes, prescribe oral and topical medications to care for peel weather, and may perform simple procedures, such as mole or wart removal. In improver, they may refer patients to an oncologist if skin cancer that has metastasized is suspected. Recently, corrective procedures have likewise become a prominent function of dermatology. Botox injections, light amplification by stimulated emission of radiation treatments, and collagen and dermal filler injections are popular among patients, hoping to reduce the advent of peel aging.

Dermatology is a competitive specialty in medicine. Limited openings in dermatology residency programs mean that many medical students compete for a few select spots. Dermatology is an highly-seasoned specialty to many prospective doctors, because unlike emergency room physicians or surgeons, dermatologists generally do not have to work excessive hours or exist "on-call" weekends and holidays. Moreover, the popularity of cosmetic dermatology has fabricated it a growing field with many lucrative opportunities. It is non unusual for dermatology clinics to market themselves exclusively as cosmetic dermatology centers, and for dermatologists to specialize exclusively in these procedures.

Consider visiting a dermatologist to talk about why he or she entered the field and what the field of dermatology is like. Visit this site for additional information.

Injuries

Considering the skin is the role of our bodies that meets the earth most directly, it is especially vulnerable to injury. Injuries include burns and wounds, also as scars and calluses. They can be caused past sharp objects, heat, or excessive pressure or friction to the skin.

Skin injuries fix off a healing process that occurs in several overlapping stages. The get-go step to repairing damaged skin is the germination of a claret clot that helps stop the menstruation of blood and scabs over with time. Many different types of cells are involved in wound repair, particularly if the surface area that needs repair is extensive. Before the basal stem cells of the stratum basale tin can recreate the epidermis, fibroblasts mobilize and divide quickly to repair the damaged tissue by collagen degradation, forming granulation tissue. Claret capillaries follow the fibroblasts and help increment blood apportionment and oxygen supply to the area. Immune cells, such as macrophages, roam the area and engulf any foreign thing to reduce the take a chance of infection.

Burns

A burn results when the skin is damaged by intense heat, radiations, electricity, or chemicals. The damage results in the death of skin cells, which tin can atomic number 82 to a massive loss of fluid. Dehydration, electrolyte imbalance, and renal and circulatory failure follow, which can exist fatal. Fire patients are treated with intravenous fluids to offset aridity, as well every bit intravenous nutrients that enable the trunk to repair tissues and replace lost proteins. Some other serious threat to the lives of burn patients is infection. Burned pare is extremely susceptible to leaner and other pathogens, due to the loss of protection by intact layers of skin.

Burns are sometimes measured in terms of the size of the total area affected. This is referred to as the "dominion of nines," which associates specific anatomical areas with a percentage that is a factor of nine (Figure 5.4.6). Burns are also classified by the degree of their severity. A kickoff-degree burn is a superficial fire that affects only the epidermis. Although the pare may be painful and swollen, these burns typically heal on their own within a few days. Balmy sunburn fits into the category of a first-caste burn. A 2d-degree burn goes deeper and affects both the epidermis and a portion of the dermis. These burns result in swelling and a painful blistering of the skin. It is important to proceed the fire site clean and sterile to forestall infection. If this is done, the burn volition heal within several weeks. A tertiary-degree burn fully extends into the epidermis and dermis, destroying the tissue and affecting the nerve endings and sensory role. These are serious burns that may appear white, ruby-red, or black; they crave medical attending and will heal slowly without it. A quaternary-degree burn is fifty-fifty more severe, affecting the underlying musculus and bone. Oddly, tertiary and 4th-caste burns are usually non as painful considering the nerve endings themselves are damaged. Full-thickness burns cannot be repaired by the body, considering the local tissues used for repair are damaged and require excision (debridement), or amputation in severe cases, followed by grafting of the skin from an unaffected office of the body, or from skin grown in tissue culture for grafting purposes.

This diagram depicts the percentage of the total body area burned when a victim suffers complete burns to regions of the body. Complete burning of the face, head and neck account for 19% of the total body area. Burning of the chest, abdomen and entire back above the waist accounts for 36% of the total body area. Anterior and posterior surfaces of the arms and hands account for 18% of the total body area (9% for each arm). The anterior and posterior surface of both legs, along with the buttocks, accounts for 36% of the total body area (18% for each leg). Finally, the anterior and posterior surfaces of the genitalia account for 1% of the total body area. — **Figure five.4.6** **– Calculating the Size of a Burn:** The size of a burn will guide decisions made almost the demand for specialized handling. Specific parts of the body are associated with a percentage of body expanse.

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Skin grafts are required when the damage from trauma or infection cannot be closed with sutures or staples. Watch this video to learn more most pare grafting procedures.

Scars and Keloids

Most cuts or wounds, with the exception of ones that merely scratch the surface (the epidermis), lead to scar formation. A scar is collagen-rich skin formed later the procedure of wound healing that differs from normal skin. Scarring occurs in cases in which in that location is repair of skin impairment, but the pare fails to regenerate the original skin structure. Fibroblasts generate scar tissue in the form of collagen, and the bulk of repair is due to the handbasket-weave pattern generated by collagen fibers and does non result in regeneration of the typical cellular structure of pare. Instead, the tissue is fibrous in nature and does not let for the regeneration of accessory structures, such equally hair follicles, sweat glands, or sebaceous glands.

Sometimes, there is an overproduction of scar tissue, considering the process of collagen formation does not stop when the wound is healed; this results in the formation of a raised or hypertrophic scar chosen a keloid. In contrast, scars that event from acne and chickenpox have a sunken advent and are called atrophic scars.

Scarring of skin afterward wound healing is a natural process and does not need to be treated further. Application of mineral oil and lotions may reduce the germination of scar tissue. Still, modern cosmetic procedures, such as dermabrasion, laser treatments, and filler injections have been invented every bit remedies for astringent scarring. All of these procedures endeavor to reorganize the construction of the epidermis and underlying collagen tissue to make it wait more than natural.

Bedsores and Stretch Marks

Skin and its underlying tissue tin be affected past excessive pressure level. One instance of this is called a bedsore. Bedsores, also called decubitis ulcers, are caused past constant, long-term, unrelieved force per unit area on sure body parts that are bony, reducing blood period to the area and leading to necrosis (tissue expiry). Bedsores are near mutual in elderly patients who have debilitating conditions that cause them to be immobile. Most hospitals and long-term care facilities accept the practice of turning the patients every few hours to prevent the incidence of bedsores. If necrotized tissue is not removed bedsores can go infected and potentially fatal.

The skin can also be affected by force per unit area associated with rapid growth. A stretch mark results when the dermis is stretched beyond its limits of elasticity, as the peel stretches to accommodate the excess pressure. Stretch marks ordinarily accompany rapid weight gain during puberty and pregnancy. They initially take a ruby-red hue, but lighten over time. Other than for corrective reasons, treatment of stretch marks is not required. They occur most commonly over the hips and abdomen.

Calluses

When you wear shoes that do non fit well and are a constant source of abrasion on your toes, you tend to form a callus at the point of contact. This occurs because the basal stem cells in the stratum basale are triggered to split more often to increase the thickness of the skin at the point of abrasion to protect the rest of the body from further impairment. This is an example of a small or local injury, and the skin manages to react and treat the problem independent of the rest of the torso. Calluses tin can besides form on your fingers if they are discipline to constant mechanical stress, such as long periods of writing, playing string instruments, physical work, or video games. A corn is a specialized form of callus. Corns grade from abrasions on the skin that result from an elliptical-blazon motion.

Chapter Review

Skin cancer is a outcome of harm to the DNA of skin cells, often due to excessive exposure to UV radiation. Basal cell carcinoma and squamous prison cell carcinoma are highly curable, and arise from cells in the stratum basale and stratum spinosum, respectively. Melanoma is the most unsafe form of peel cancer, affecting melanocytes, which can spread/metastasize to other organs. Burns are an injury to the skin that occur as a result of exposure to extreme heat, radiations, or chemicals. Offset-caste and second-caste burns usually heal quickly, but 3rd-degree burns tin can be fatal considering they penetrate the total thickness of the skin. Scars occur when at that place is repair of peel impairment. Fibroblasts generate scar tissue in the form of collagen, which forms a basket-weave blueprint that looks unlike from normal pare.

Bedsores and stretch marks are the effect of excessive pressure level on the skin and underlying tissue. Bedsores are characterized by necrosis of tissue due to immobility, whereas stretch marks result from rapid growth. Eczema is an allergic reaction that manifests as a rash, and acne results from clogged sebaceous glands. Eczema and acne are usually long-term peel atmospheric condition that may be treated successfully in mild cases. Calluses and corns are the result of abrasive pressure on the skin.

Review Questions

Critical Thinking Questions

one. Why do teenagers often feel acne?

2. Why exercise scars await different from surrounding pare?

References

American Cancer Gild (US). Skin cancer: basal and squamous cell [Net]. c2013 [cited 2012 Nov 1]. Available from: http://www.cancer.org/acs/groups/cid/documents/webcontent/003139-pdf.pdf.

Lucile Packard Children's Infirmary at Stanford (US). Classification and treatment of burns [Internet]. Palo Alto (CA). c2012 [cited 2012 November 1]. Available from: http://www.lpch.org/diseasehealthinfo/healthlibrary/burns/classify.html.

Mayo Dispensary (US). Basal cell carcinoma [Internet]. Scottsdale (AZ); c2012 [cited 2012 November 1]. Available from: http://world wide web.mayoclinic.com/health/basal-jail cell-carcinoma/ds00925/dsection=treatments-and-drugs.

Beck, J. FYI: how much can a man trunk sweat earlier information technology runs out? Pop Science [Internet]. New York (NY); c2012 [cited 2012 Nov 1]. Available from:http://world wide web.popsci.com/science/commodity/2011-01/fyi-how-much-can-human-torso-sweat-information technology-runs-out.

Skin Cancer Foundation (U.s.a.). Skin cancer facts [Internet]. New York (NY); c2013 [cited 2012 Nov ane]. Available from: http://world wide web.skincancer.org/pare-cancer-information/skin-cancer-facts#height.

Glossary

acne: skin condition due to infected sebaceous glands

basal cell carcinoma: cancer that originates from basal cells in the epidermis of the peel

bedsore: sore on the skin that develops when regions of the torso kickoff necrotizing due to constant pressure and lack of blood supply; also called decubitis ulcers

callus: thickened area of skin that arises due to constant chafe

corn: blazon of callus that is named for its shape and the elliptical motion of the annoying force

eczema: skin condition due to an allergic reaction, which resembles a rash

start-degree fire: superficial burn that injures merely the epidermis

4th-degree burn: burn in which full thickness of the skin and underlying muscle and bone is damaged

keloid: type of scar that has layers raised above the skin surface

melanoma: type of skin cancer that originates from the melanocytes of the skin

metastasis: spread of cancer cells from a source to other parts of the torso

scar: collagen-rich skin formed after the process of wound healing that is different from normal skin

2d-degree burn down: partial-thickness burn that injures the epidermis and a portion of the dermis

squamous prison cell carcinoma: blazon of skin cancer that originates from the stratum spinosum of the epidermis

stretch marking: mark formed on the skin due to a sudden growth spurt and expansion of the dermis beyond its elastic limits

tertiary-degree fire: fire that penetrates and destroys the full thickness of the skin (epidermis and dermis)

Solutions

Answers for Disquisitional Thinking Questions

Acne results from a blockage of sebaceous glands by sebum. The blockage causes blackheads to form, which are susceptible to infection. The infected tissue then becomes carmine and inflamed. Teenagers experience this at high rates because the sebaceous glands become active during puberty. Hormones that are particularly agile during puberty stimulate the release of sebum, leading in many cases to blockages.
Scars are made of collagen and practice non accept the cellular construction of normal skin. The tissue is fibrous and does not allow for the regeneration of accessory structures, such equally hair follicles, and sweat or sebaceous glands.