Skin, Hair, and Nails Flashcards
The epidermis is thin but tough. Its cells are bound tightly together into sheets that form a rugged protective barrier. Jt is stratified into several zones.
The inner basal cell layer forms new skin cells. Their major ingredient is the tough, fibrous protein keratin.
From the basal layer the new cells migrate up and flatten into the outer horny cell layer. This consists of dead keratinized cells that are interwoven and closely packed. The cells are constantly being shed, or desquamated, and are replaced with new cells from below. The epidermis is completely replaced every 4 weeks. ln fact, each person sheds about 1 pound of skin each year. The epidermis is uniformly thin except on the surfaces that are exposed to friction, such as the palms and the soles.
Skin color is derived from three sources: (1) mainly from the brown pigment melanin, (2) also from the yellow-orange tones of the pigment carotene, and (3) from the red-purple tones in the underlying vascular bed.
Epidermis
The dermis is the inner supportive layer consisting mostly of connective tissue, or collagen. This is the tough, fibrous protein that enables the skin to resist tearing.
Also has resilient elastic tissue that allows the skin to stretch with body movements.
The nerves, sensory receptors, blood vessels, and lymphatics lie in.
Also, appendages from the epidermis- such as the hair follicles, sebaceous glands, and sweat glands-are embedded in the dermis.
Dermis
Is adipose tissue, which is made up of lobules of fat.
Stores fat for energy, provides insulation for temperature control, and aids in its soft cushioning layer.
Also gives skin its increased mobility over structures underneath.
Subcutaneous layer
Are threads of keratin.
The hair shaft is the visible projecting part, and the root is below the surface embedded in the follicle.
At the root the bulb matrix is the expanded area where new cells are produced at a high rate.
Hair growth is cyclical, with active and resting phases.
Around the hair follicle are the muscular arrector pili, which contract and elevate the hair so that it resembles “goose flesh” when the skin is exposed to cold or in emotional state.
People have two types of hair.
1.Fine, faint vellus hair covers most of the body (except the palms and soles, the dorsa of the distal parts of the fingers, covers most of the body (except the palms and soles, the dorsa of the distal parts of the fingers, the umbilicus, the glans penis, and inside the labia).
2. The other type is terminal hair, the darker, thicker hair that grows on the scalp and eyebrows and, after puberty, on the axillae, the pubic area, and the face and chest in the male.
Hair
These glands produce a protective lipid substance, sebum, which is secreted through the hair follicles.
Sebum oils and lubricates the skin and hair and forms an emulsion with water that retards water loss from the skin. (Dry skin results from loss of water, not directly from loss of oil.) are everywhere except on the palms and soles.
They are most abundant in the scalp, forehead, face, and chin.
Sebaceous Glands
The eccrine glands are coiled tubules that open directly onto the skin surface and produce a dilute saline solution called sweat. The evaporation of sweat reduces body temperature.
Eccrine glands are widely distributed through the body and are mature in the 2-monthold infant.
The apocrine glands produce a thick, milky secretion and open into the hair follicles. They are located mainly in the axillae, anogenital area, nipples, and navel and are vestigial in humans. They become active during puberty, and secretion occurs with emotional and sexuaJ stimulation. Bacterial flora residing on the skin surface react with apocrine sweat to produce a characteristic musky body odor. The functioning of apocrine glands decreases in the aging adult.
Sweat Glands
Are hard plates of keratin on the dorsal edges of the fingers and toes.
The nail plate is clear, with fine longitudinal ridges that become prominent in aging.
Nails take their pink color from the underlying nail bed of highly vascular epithelial cells.
The lunula is the white, opaque, semilunar area at the proximal end of the nail. It
Nails
The skin is a waterproof, almost indestructible, covering that has protective and adaptive properties: Protection. Skin minimizes injury from physical, chemical, thermal, and light-wave sources.
• Prevents penetration. Skin is a barrier that stops invasion of microorganisms and loss of water and electrolytes from within the body.
• Perception. Skin is a vast sensory surface holding the neurosensory end-organs for touch, pain, temperature, and pressure.
• Temperature regulation. Skin allows heat dissipation through sweat glands and heat storage through subcutaneous insulation. -Identification. People identify one another by unique combinations of facial characteristics, hair, skin color, and even fingerprints.
-Self-image is often enhanced or deterred by the way society’s standards of beauty measure up to each person’s perceived characteristics.
Communication. Emotions are expressed in the sign language of the face and in the body posture. Vascular mechanisms such as blushing or blanching also signal emotional states. Wound repair. Skin allows ceU replacement of surface wounds.
• Absorption and excretion. Skin allows limited excretion of some metabolic wastes, byproducts of cellular decomposition such as minerals, sugars, amino acids, cholesterol, uric acid, and urea.
• Production of vitamin D. The skin is the surface on which ultraviolet light converts cholesterol into vitamin D.
FUNCTION OF THE SKIN
The hair follicles develop in the fetus at 3 months’ gestation; by midgestation, most of the skin is covered with lanugo, the fine downy hair of the newborn infant. In the first few months after birth, this is replaced by fine vellus hair.
Terminal hair on the scalp, if present at birth, tends to be soft and to suffer a patchy loss, especially at the temples and occiput.
Also present at birth is vernix caseosa, the thick, cheesy substance made up of sebum and shed epithelial cells.
The infant is at greater risk for fluid loss. Sebum, which holds water in the skin, is present for the first few weeks of life, producing milia (see p. 222) and cradle cap in some babies.
The sebeaous glands decrease in size and production and do not resume functioning until puberty.
At puberty, secretion from apocrine sweat glands increases in response to heat and emotional stinmli, producing body odor. Sebaceous glands become more active-the skin looks oily, and acne develops. Subcutaneous fat deposits increase, especially in females.
Secondary sex characteristics that appear during adolescence are evident in the integument (i.e., skin). In the female, the diameter of the areola enlarges and darkens and breast tissue develops. Coarse pubic hair develops in males and females.
Development competence
Infant and children
The change in hormone levels results in increased pigment in the areolae and nipples, vulva, and sometimes in the midline of the abdomen (linea nigra) or in the face (chloasma). Striae gravidarum (stretch marks), which may develop in the skin of the abdomen, breasts, or thighs. Metabolism is increased in pregnancy; as a way to dissipate heat, the peripheral vasculature dilates and the sweat and sebaceous glands increase secretion. Fat deposits are laid down, particularly in the buttocks and hips, as maternal reserves for the nursing baby.
Development competence
The pregnant women
The aging skin loses its elasticity; it folds and sags. By the 70s to 80s, it looks parchment thin, lax, dry, and wrinkled.
The epidermis’s outer layer thins and flattens.
This allows chemicals easier access into the body. Wrinkling occurs because the underlying dermis thins and flattens. A loss of elastin, collagen, and subcutaneous fat occurs as well as a reduction in muscle tone.
The loss of collagen increases the risk for shearing, tearing injuries.
Sweat glands and sebaceous glands decrease in number and function, leaving dry skin.
Decreased response of the sweat glands to thermoregulatory demand also puts the aging person at greater risk for heat stroke. The vascularity of the skin diminishes while the vascular fragility increases; a minor trauma may produce dark red discolored areas, or senile purpura.
Sun exposure and cigarette smoking further accentuate aging changes in the skin.
Coarse wrinkling, decreased elasticity, atrophy, speckled and uneven coloring, more pigment changes, and a yellowed, leathery texture occur.
Chronic sun damage is even more prominent in pale or light-skinned persons.
An accumulation of factors place the aging person at risk for skin disease and breakdown: the thinning of the skin, the decrease in vascularity and nutrients, the loss of protective cushioning of the subcutaneous layer, a lifetime of environmental trauma to skin, the social changes of aging (e.g., less nutrition, limited financial resources), the increasingly sedentary lifestyle, and the chance of immobility. When skin breakdown does occur, subsequent cell replacement is slower and wound healing is delayed.
The female’s estrogen also decreases, testosterone is unopposed and the female may have some bristly facial hairs.
Nails grow more slowly.
Developmental competence
The aging adult
As described earlier, mela11in is responsible for the various colors and tones of skin observed among people. Melanin protects the skin against harmful ultraviolet rays, a genetic advantage accounting for the lower incidence of skin cancer among darkly pigmented Blacks and American Indians. The incidence of melanoma is 20 times higher among whites than among Blacks and 4 times higher among whites than among Hispanics.
The apocrine and eccrine sweat glands are important for fluid balance and for tl1ennoregulation. When apocrine gland secretions are contaminated by normal skin flora, odor results.
Cultural genetics
I. Keloids-scars that form at the site of a wound and grow beyond the normal boundaries of the wound (see p. 235)
- Areas of either postinflammatory hypopigmentation or hyperpigmentation that appear as dark or light spots
- Pseudofolliculitis- “razor bumps” or “ingrown hairs” caused by shaving too closely with an electric razor or straight razor 4. Melasma-the “mask of pregnancy:’ a patchy tan to dark brown discoloration of the face
Skin conditions found amount blacks
1.. Past history of skin disease
4. Excessive dryness or moisture (allergies, hives, psoriasis,
5. Pruritus eczema)
6. Excessive bruising
2. Change in pigmentation
7. Rash or lesion
3. Change in mole (size or color)
8. Medications
9.Hair loss
10. Change in nails
11 . Environmental or occupational hazards
12. Self-care behaviors
Subjective Data
Hypopigmentation (loss of color);
hyperpigmentation (increase in color).
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Change in pigmentation. Any change in skin color or pigmentation?
Generalized change suggests systemic illness: pallor, jaundice, cyanosis.
Any change in a mole: color, size, shape, sudden appearance of tenderness, bleeding, itching?
Signs suggest neoplasm in pigmented nevus.
Seborrhea-oily. Xerosis-dry.
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Any skin itching?
Pruritus is the most common skin symptom; occurs with dry skin, aging, drug reactions, allergy, obstructive jaundice, uremia, lice.
Scratching causes excoriation of primary lesion.
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Any excess bruising?
Multiple cuts and bruises, bruises in various stages of healing, bruises above knees and elbows, and illogical explanation -consider physical abuse.
Frequent falJs may be due to dizziness of neurologic or cardiovascular ongm.
Also, frequent minor trauma may be a side effect of alcoho.lism or other drug abuse.
Rashes are a common cause of seeking health care.
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Drugs may cause allergic skin eruption: aspirin, antibiotics, barbiturates, some tonics.
Drugs may increase sunlight sensitivity and give burn response: sulfonamides, thiazide diuretics, oral hypoglycemic agents, and tetracycline.
Drugs can cause hyperpigmentation: antimalarials, antineoplastic agents, hormones, metals, tetracycline.
What medications do you take?
Alopecia is a significant loss.
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Environmental or occupational hazards. Any environmental or occupational hazards?
People at risk: outdoor sports enthusiasts, farmers, sailors, outdoor workers; also creosote workers, roofers, coal workers.
Unprotected sun exposure accelerates aging and produces lesions. At more risk: light-skinned people, those older than 40 years, and those regularly in sun.
Additional History for Infants and Children
Generalized rash–consider allergic reaction to new food
irritability and general fussiness may indicate the presence of pruritus.
Occlusive diapers or infrequent changing may cause rash. Infant may be allergic to certain detergent or to disposable wipes.
contagious skin conditions: scabies, impetigo, lice.
communicable diseases: measles, chickenpox, scarlet fever? Or to toxic plants: poison ivy?
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habitual movements, such as nail-biting, twisting hair, rubbing head on mattress.
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Excessive sun exposure, especially severe or blistering sunburns in childhood, increases risk for melanoma in later life.
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Additional History for the Adolescent
Cause is unknown; acne is not caused by poor diet, oily complexion, or contagion.
Normal aging changes may cause distress.
Many “aging” changes are due to chronic sun damage.
Most skin cancers appear in aging people, although sun damage begins decades earlier.
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Pruritus is common with aging
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Also, some aging people tolerate chronic pain as “part of growing old” and hesitate to “complain.”
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A bland lotion is important to retain moisture in aging skin.
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Dermatitis may ensue from certain cosmetics, creams, ointments, and dyes applied to achieve a youthful appearance.
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Aging skin has a delayed inflammatory response when exposed to irritants
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An acquired condition is vitiligo, the complete absence of melanin pigment in patchy areas of white or light skin on the face, neck, hands, feet, body folds, and around orifices.
Vitiligo can occur in all races, although dark-skinned people are more severely affected and potentially suffer a greater threat to their body image.
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Freckles (ephelides)-small, flat macules of brown melanin pigment that occur on sun-exposed skin
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Mole (nevus)- a proliferation of melanocytes, tan to brown color, flat or raised. Acquired nevi are characterized by their symmetry, small size (6 mm or less), smooth borders, and single uniform pigmentation.
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The junctional nevus (Fig. 12-4, B) is macular only and occurs in children and adolescents. It progresses to the compound nevi in young adults (Fig. 12-4, C) that are macular and papular.
The intradermal nevus (mainly in older age) has nevus cells in only the dermis.
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pallor (white),
erythema (red),
cyanosis (blue), and
jaundice (yellow).
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Pallor. When the red-pink tones from the oxygenated hemoglobin in the blood are lost, the skin takes on the color of connective tissue (collagen), which is mostly white.
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Erythema. Erythema is an intense redness of the skin from excess blood (hyperemia) in the dilated superficial capillaries. This sign is expected with fever, with local inflammation, or with emotional reactions such as blushing in vascular flush areas (cheeks, neck, and upper chest).
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Erythema occurs with polycythemia, venous stasis, carbon monoxide poisoning, and the extravascular presence of red blood cells (petechiae, ecchymosis, hematoma)
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Cyanosis. This is a bluish mottled color that signifies decreased perfusion; the tissues do not have enough oxygenated blood.
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Cyanosis indicates hypoxemia and occurs with shock, heart failure, chronic bronchitis, and congenital heart disease.
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Jaundice. A yellowish skin color indicates rising amounts of bilirubin in the blood.
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Jaundice occurs with hepatitis, cirrhosis, sickle-cell disease, transfusion reaction, and hemolytic disease of the newborn.
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Light or clay-colored stools and dark golden urine often accompany jaundice in both light- and dark-skinned people.
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Hypothermia. Generalized coolness may be induced, such as in hypothermia used for surgery or high fever. Localized coolness is expected with an immobilized extremity, as when a limb is in a cast or with an intravenous infusion.
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General hypothermia accompanies central circulatory problem such as shock.
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Localized hypothermia occurs in peripheral arterial insufficiency and Raynaud’s disease.
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Hyperthermia. Generalized hyperthermia occurs with an increased metabolic rate, such as in fever or after heavy exercise. A localized area feels hyperthermic with trauma, infection, or sunburn.
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Hyperthyroidism has an increased metabolic rate, causing warm, moist skin.
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Diaphoresis, or profuse perspiration, accompanies an increased metabolic rate, such as occurs in heavy activity or fever.
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Diaphoresis occurs with thyrotoxicosis and with stimulation of the nervous system with anxiety or pain.
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Be aware that dark skin may normally look dry and flaky, but this does not necessarily indicate systemic dehydration.
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With dehydration, mucous membranes are dry, and lips look parched and cracked.
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reason for seeking care
CC
health habits
tobacco alcohol drugs
vitamin A
apricotts peaches caarrots spinach
vitamin C
oranges lemons grapefruit strawbarries tomatooes
vitamin E
lettuce alflfa and vegtable oills
Hyperthyroidism-skin feels smoother and softer, like velvet.
Hypothyroidism-skin feels rough, dry, and flaky.
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Very thin, shiny skin (atrophic) occurs with arterial insufficiency.
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1+ Mild pitting, slight indentation, no perceptible swelling of the leg
2+ Moderate pitting, indentation subsides rapidly
3+ Deep pitting, indentation remains for a short time, leg looks swollen
4+ Very deep pitting, indentation lasts a long time, leg is very swollen
Pitting edema grading scale
Edema makes the hair follicles more prominent, so you note a pigskin or orange-peel look (called peau d’orange).
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Bilateral edema or edema that is generalized over the whole body (anasarca)-consider a central problem such as heart failure or kidney failure.
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Poor turgor is evident in severe dehydration or extreme weight loss; the pinched skin recedes slowly or “tents” and stands by itself.
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Scleroderma, literally “hard skin,” is a chronic connective tissue disorder associated with decreased mobility
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