chapter 46 disorders of skin integrity and function

Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins

Chapter 46Disorders of Skin Integrity and

Function


Skin Infections• Superficial fungal infections

– Ringworm, athlete’s foot– Attack the keratinized (dead) cells– Inflammatory reaction to toxins causes

most signs and symptoms• Deep fungal infections

– Candidiasis, sporotrichosis– Attack living tissue– May attack other organs


Bacterial Skin Infections

• Impetigo– May lead to post-

streptococcal hypersensitivity reactions

– These can cause glomerulonephritis


Viral Skin Infections• Verrucae (warts)

– Benign neoplasms (papillomas)• Herpes simplex (cold sores)• Herpes zoster (shingles)

– Herpes invades dorsal root ganglia– Caused when chickenpox herpesvirus is reactivated– Travels out nerve to skin and causes a new

inflammation


Question

Which of the following microbes cause warts?a. Fungusb. Virusc. Bacteriad. Any of the above may cause warts.


Answer

b. VirusWarts are caused by viruses; they’re benign neoplasms

(abnormal tissue growths).


ScenarioMrs. K is worried about her complexion…• She says she always had good skin, but now

her face itches and burns on the right side, and there are red lumps on one side of her forehead

Question• What are the possible causes?


Acne

• Disorder of sebaceous glands• Related to:

– Hormonal stimulation of sebaceous glands– Increased number of sebaceous cells– Increased sebum production– Inflammatory response to bacteria in sebum


Allergic and Hypersensitivity Dermatoses

• Type I allergies– Atopic eczema– Urticaria (hives)


Type I AllergiesType I allergies are mediated by IgE

Discussion• What cells must be involved in this process?

– On the first exposure to the allergen?– On repeated exposure?– When the allergen binds to IgE?

• What inflammatory mediators are involved? How?


Question

Which chemical mediator is released by mast cells as part of the inflammatory response?

a. Histamineb. Leukotrienec. Cytokined. All of the above


Answer

a. HistamineHistamine (stored in mast cells) is one of the first

substances to be released during the inflammatory response. Histamine release results in bronchoconstriction, mucosal edema, and increased mucus production.


Autoimmune Urticaria

In autoimmune urticaria, the client creates anti-IgE antibodies

Discussion• How would this cause hives?• How would a deficiency in complement inhibitor

cause hives?• Why would antihistamines help?• Why would corticosteroids help?


Drug-Induced Skin Eruptions• Erythema multiforme

– Occurs after herpes simplex; self-limiting• Stevens-Johnson syndrome

– Skin detaches from body surface; <10% of body affected

• Toxic epidermal necrolysis– >30% of epidermis detaches– 30%–35% mortality rate


Papulosquamous Dermatoses• Psoriasis• Pityriasis rosea• Lichen planus


PsoriasisActivated

T cells

growth factors

keratinocytes and blood

vessels grow

create papules

attract neutrophils

and monocytes

enter the

papules

create inflammation


Burns• First-degree: outer layers of epidermis• Second-degree: epidermis and dermis

– Partial-thickness: only part of dermis– Full-thickness: entire dermis

• Third-degree full-thickness– Extends into subcutaneous tissue– May damage muscle, bone, blood vessels


ScenarioMr. D was boiling water and the pot tipped over

on him…• He has painful, bright pink, blistering burns

over most of his left arm and chest

Question• How would you categorize this burn?


Scenario (cont.)Mr. D's burns are pink but the rest of his body

looks pale, and he has a rapid heart rate…• His pulses are weak • Bowel sounds are absent • Respiration is rapid Question• What has caused these signs?


Complications of Burns

• Burn shock• Respiratory system dysfunction• Hypermetabolic response• Renal insufficiency• Gastric ulceration• Sepsis• Constriction of areas under circumferential burns• Systemic infection


ScenarioA woman was severely burned and she has been in

the hospital for eight days

Question • Why would she be developing:

– Increased urine production?– Weight loss?– Increased temperature?– GI bleeding?


Question

Treatment for third-degree burn patients includes all but which of the following?

a. Fluid replacementb. Removal of dead tissue/escharc. Antibioticsd. Aloe


Answer

d. AloePatients suffering from third-degree (full thickness) burns

lose fluid through the skin and are prone to infection. They must receive fluid replacement and antibiotics to fight or prevent infection. Dead tissue (eschar) must be removed daily (debridement) in order to prevent infection. Because third-degree burns destroy the epidermis, the application of topical aloe would serve no purpose.


Pressure Sores

External pressure

obstructs blood flow

ischemia to skin

tissue damage

Shear

bends blood vesselsFriction

damages dermis/

epidermis interface


Ultraviolet radiation

hits melanocytes

melanin oxidized - TAN

some UV reaches lower skin layers

immune cells

damagedinflammatory

mediators released

DNA damage

sunburn

more melanin produced - delayed

tanning


Sun Exposure• Sun exposure increases the risk of skin cancer• Cumulative sun exposure increases risk of:

– Basal cell carcinoma– Squamous cell carcinoma

• Severe sun exposure with blistering increases risk of:– Malignant melanoma


Malignant Melanoma

• Cancers arising from melanocytes• Asymmetry• Border irregularity• Color variegation• Diameter >0.6 cm• Evolving change over time


Types of Melanomas• 70% are superficial spreading

– Raised edges; grow horizontally and vertically– Ulcerate and bleed

• 15%–30% are nodular– Dome-shaped, blue-black

• 4%–10% are lentigo maligna– Slow growing, flat

• 2%–4% acral lentiginous– On palms, soles, nail beds, mucous membranes


Question

Which type of skin cancer is associated with the worst prognosis?

a. Basal cellb. Squamous cellc. Malignant melanomad. Ependymal cell


Answer

c. Malignant melanomaMalignant melanoma begins in the melanocytes, and

possesses all of the characteristic features associated with cancer (asymmetry, irregular border, many colors, and a diameter >0.6 cm) as defined by the American Cancer Society.

Basal cell cancer has the best prognosis, and squamous cell cancer has a good prognosis as long as it is detected early.


Skin Conditions of Infancy

• Birthmarks• Diaper dermatitis• Prickly heat• Cradle cap• Infectious disease rashes

– Roseola (herpesvirus)– Rubeola (measles)– Rubella (German measles)– Varicella (chickenpox)


Skin Disorders of the Elderly

• Actinic (solar) damage– Keratoses: premalignant lesions– Lentigines: liver spots

• Vascular lesions– Angiomas– Telangiectases– Venous lakes

chapter 46 disorders of skin integrity and function

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