Skin overview

what are the functions of the skin?

physical barrier, immunologic functions, temperature regulation, protection from radiation, nerve sensation, injury repair

describe the function of the skin as a physical barrier

regulates water loss, protects against mechanical/chemical/microbial insults

dysfunction leads to: dehydration, injury, infection, and inflammation.

describe the skin’s immunologic functions

senses and responds to pathogens — Langerhans Cell in epidermis, part of cell mediated immune response

dysfunction leads to: infection, skin cancer, inflammation, allergy

describe the skin’s role in temperature regulation

insulation via fat and hair

cooling via sweat and superficial microvasculature

dysfunction leads to: overheating, hypothermia, Raynaud’s Phenomenon

describe how the skin provides protection from radiation and what dysfunction leads to

pigmentation (melanin)

dysfunction leads too:

• Xeroderma Pigmentosum: decreased ability to repair DNA

• Albinism: skin, hair, or eyes have little or no color

• Vitiligo: white patches on skin

describe nerve sensations related to the skin

sensory receptors for physical interactions

dysfunction can lead too: pruritis, dysesthesia (painful, burning, itchy sensation), insensitivity to injury

describe how to skin repairs injuries

coagulation, inflammation, proliferative/migratory (tissue formation), and remodeling phases

dysfunction can lead to: delayed wound healing

describe the skin’s effect on quality of life

psychological aspects of damage or defects

dysfunction can lead to: anxiety, depression, etc

what is the endocrine role of the skin?

sun converts to vitamin D!

several hormones are activated or deactivated by skin

what is excreted through the skin?

water, ammonia, uric acid, alcohol, salicylic acid, heavy metals

methamphetamine/amphetamine in sweat

what is the largest organ of the body?

the skin

what are the three layers of the skin?

Epidermis, Dermis, and Hypodermis

what is the epidermis composed of?

consists primarily of keratinocytes

what is the dermis composed of?

fibroblasts, collagen, elastin

what is the hypodermis composed of?

fat, sweat glands, hair grows

what are filaggrin and keratin?

important proteins in barrier function

filaggrin protein mutations are thought to contribute to skin conditions such as _____________________

eczema and chronic dry skin

what is keratin’s role?

is a protein that helps protect the outer later of skin from water loss, UV radiation, and other skin stressors

which skin protein prevents the invasion of allergens/extrinsic stimuli?

filaggrin

what are melanocytic nevi?

Moles which are benign collections of melanocytes

what is the ABCDE rule for identifying melanomas?

A is asymmetry: one-half of mole doesn’t match other

B is for border: irregular borders

C is for color: not the same color or diff shades

D is for diameter: > 6 mm across

E is for evolving: mole is changing in size/shape/color

what is melanoma?

a malignancy of melanocytes

what are macules?

flat colored spots

what are papules?

raised colored spots

how can you differentiate between a macule and papule?

dim lights, shine pen light at right angle to lesion, if a shadow is cast, then it’s a papule (<1.5 cm diameter)

macules have no shadow and <1.5 cm diameter

nodule bump has shadow and > 1.5 cm diameter

what are patches or plaques?

patch is a colored spot (larger than papule)

plaque is a raised patch (larger than papule)

what are the different types of fluid filled lesions, “blisters”?

vesicles (fluid)

bullae (is vesicle > 2 cm diameter, fluid)

pustules (pus)

how do you decipher if a lesion is fluid filled or not?

place a tip of penlight against lesion — solid lesions do not transmit light, while fluid filled lesions fill with a red “glow”

which things have proliferation into the dermis?

cyst (liquid) and nodules (solid)

what is a fissure?

“crack” linear, cleavage

what is erosion?

loss of epidermis — weeping, crusting, and usually no scar

what is an ulcer?

loss of epidermis and part of dermis — can become infected, and often heal with scars

what is excortiation?

erosion or ulcer caused by scratching

what are wheals and flares?

may be from allergic reaction but can be from other causes: wheal is the swelling and release of serum in tissue (bump on skin), while flare is the dilation of blood vessels (erythema)

what is a burrow?

often seen with scabies — the trail they leave under the skin

what is a sinus?

hole in the skin (cutie cole’s ear)

what is striae?

basically stretch marks

what are petechiae?

round spots on skin when capillaries break open, pinpoint, < 4 mm, can be red/brown/or purple

negative diascopy (do not lose color when you press on them)

what is purpura?

when the petechiae dots combine into a big “dot” — 4-10 mm petechiae, can be red/brown/or purple

negative diascopy (do not lose color when you press on them)

what is telangiectasia?

small dilated blood vessels, red or purple, “spider veins,” or “broken blood vessels”

what is lichenification?

thickening of skin

what is ecchymosis?

discoloration of the skin (>10 mm)

what are scales?

fine and desquamation that occurs in cold weather, low moisture air, meds, and from soaps

what is ichthyosis?

hereditary, thick, dry, fish scale like

what are some of the causes for telangiectasia?

aging, rosacea, pregnancy, sun exposure/damage, and varicose veins

what are some of the causes for petechiae/purpura?

infection and reactions to medications (nitrofurantoin, penicillin)

what is a bruise?

falls under umbrella of ecchymosis — injury to small blood vessels under skin, also known as contusion

what is a hematoma?

falls under umbrella of ecchymosis — blood pools and is trapped outside blood vessels, may not be seen

which medications can cause desquamation?

phenytoin and sulfa drugs

what is diascopy?

test for blanchability by applying pressure with finger or glass slide

what is the diascopy of inflammatory lesions (psoriasis, urticaria, eczema)?

(+) diascopy

what is the diascopy of hemorrhagic lesions (petechiae-steroid induced atrophy of bv)?

(-) diascopy

what is the diascopy of nonvascular lesions (mole with distinct edges)?

(-) diascopy

what is a positive diascopy?

skin blanches

what is a negative diascopy?

skin does not blanch

what are the different shapes of papules?

dome shaped, flat topped, umbilicated, acuminate, verrucous, pedunculated

what is this image?

annular/polycyclic/grouped

what is this image?

reticular (can occur from minocycline or amantadine)

what is this image?

arcuate

what is this?

serpiginous

what is this image?

whorled

what is this image?

linear

what is this image?

targetoid

what does intertriginous mean?

skin folds

what does acral mean?

peripheral

what are dermatomes?

an area of skin that is supplied by a single nerve

what is lymphangitic?

transport WBCs in the body, rid body of toxins (something follows the lymph nodes)

what is cellulitis?

skin infection — red, swollen, warm to touch, painful, pus

what is impetigo?

group A b-hemolytic Streptococcus pyogenes (presents with yellow, silver grey/honey colored crust)

what is folliculitis?

infected hair follicle (not cellulitis)

what is furuncle?

(boil) cellulitis arising from single hair follicle

what is carbuncle?

large furuncle with cellulitis contains multiple hair follicles that has connecting around cuticle

what is paronychia?

cellulitis around cuticle

what is necrotizing fasciitis?

“flesh eating bacteria,” multi-organism, aerobic/anaerobic, often GABHS, may lose soft tissue

what evaluation/questions should be done to describe skin integrity?

intact or presents with injury? classify the type of injury, describe the type/shape/arrangement and distribution of injury/lesion

types of wounds (puncture/hole, abrasions, laceration, contusion, burns)

what are the pressure ulcer scale stages?

Stage 1: just erythema of the skin

Stage 2: erythema with the loss of partial thickness of the skin including epidermis and part of the superficial dermis

Stage 3: full thickness ulcer that might involve the subcutaneous fat

Stage 4: full thickness ulcer with the involvement of the muscle or bone

what is edema?

swelling d/t excess fluid (note location), pitting vs. non-pitting (grade 4 is deeper than grade 1)

what evaluation/questions should be done to review sensory status?

determine if intact or altered

if issues, not where: loss of protective sensation, two-point discrimination (touch test), temperature (can pt discriminate warm/cold), deep pressure, pin prick

how does dry skin present?

flaking, scales, fissures, cracks

how does moist skin present?

sweat, incontinence, weeping, exudate

what do atrophic changes of the skin look like/mean?

shiny or hairless extremities “tobacco paper skin”

might indicate vascular compromise (or age, or excessive topical steroid use)

what can effect skin turgor/texture?

Skin that isn’t intact may be caused by irritation or trauma. Rough skin may be caused by dermatologic or systemic conditions (eczema, psoriasis)

define turgor

elasticity of skin (poor marker in dehydrated or edematous patients, or in the elderly but not reliable marker of hydration)

what is skin texture?

scar tissue forms when wound heal, different texture/quality than normal skin, may cause cosmetic concerns/patient distress

what are acne scars?

pitting, sunken recesses

what are contracture scars?

tightening of skin may impede mobility

what are hypertrophic scars?

red, raised bump does not exceed wound boundaries (surgery scars)

what are keloid scars?

overgrowth of colloid/granulation tissue results in benign tumorous growth (trauma, piercings, ance, surgery)

what evaluation/questions should be done to describe nails and hair?

nails — reflect patients health (color, shape, contour, clubbing, texture, thickness)

hair:

• too much in females? hirsutism

• too little? alopecia

  • brittle, dry hair? sx of underlying disease or excess care

what evaluation/questions should be done when evaluating skin color?

normally smooth, slightly most, and same tone throughout

tone = melanocyte concentration

note color of skin and uniformity (color may serve to confirm diagnosis, or may be diagnostic)

hypopigmented or hyperpigmented

what is the distribution of absent color?

small, circumscribed areas, generalized

what are the possible causes/terminology for absent color?

vitiligo - loss of skin color in blotches

albinism - genetic, partial, or complete loss of color in skin, eyes, and hair

what is the distribution of blue colored skin?

around lips, buccal mucosa, or generalized

what are the possible causes/terminology for blue skin?

cyanosis (in African Americans, blue gingivae are normal)

what is the distribution for deep red colored skin?

generalized

what are the possible causes/terminology for deep red colored skin?

polycythemia vera — type of cancer that makes too many RBCs

what is the distribution of pink skin?

local or generalized

what are the possibel causes/terminology for pink skin?

erythema

what is the distribution of tan/brown colored skin?

facial patches

what are the possible causes/terminology for tan/brown skin?

chloasma, butterfly rash (SLE)