Studied by 6 people
What are the layers of the epidermis? (sup → inf)
coreum, lucidum, granulosum, spinosum, basale
(come lets get sun burnt)
What are the layers of the dermis? (sup → inf)
papillary, reticular
What does the epidermis layer contain?
keratinocytes, melanocytes, Langerhans cells
What does the hypodermis layer contain?
adipose tissue, sensory neurons, blood vessels, hair follicles
What does the reticular layer of the dermis contain?
dense connective tissue and collagen fiber bundles
What do keratinocytes do?
produce keratin and lipids, form the epidermal water barrier, enable UVB absorption to activate vit D
What do melanocytes do?
produce pigment, stimulate melanin production to protect against UV radiation
What is the largest organ of the body?
skin
What is used to describe a person’s skin tone and the risk of burning or tanning in response to UV radiation?
Fitzpatrick Scale
What is a primary lesion?
beginning lesion of a skin disease
What is a macule?
non-palpable lesions that vary in pigmentation < 1cm
What is a patch?
non-palpable lesions that vary in pigmentation > 1cm
What are examples of macules/patches?
vitiligo, cafe-au-lait spots, mongolian spots, melanocytic nevus, freckles, petechiae
What are purpura?
red-purple lesions that do NOT blanch under pressure due to extravasation of blood from cutaneous vessels into the skin
What is a papule?
palpable discrete lesions < 0.5 cm
What is a plaque?
palpable, plateau-like discrete lesion > 0.5 cm
What is a nodule?
1-2 cm well-circumscribed solid or cystic lesion; can be superficial or deep
What is a tumor?
> 2cm solid or cystic lesion; can be superficial or deep
What is telangiectasia?
small, cherry red dilatations of the venules (spider vessels)
What disease is Telangiectasia commonly seen in?
rosacea
What are pustules?
small, circumscribed skin papule containing purulent material
What is special about follicular pustules?
usually contain a hair in the center; are conical or dome shaped
What are vesicles?
small < 5mm circumscribed papules containing clear, serous or hemorrhagic fluid; superficial, well-defined
What are bullae?
large > 5mm circumscribed vesciles
What are examples of dome-shaped vesicles?
contact dermatitis, dermatitis herpetiformis
What are examples of umbilicated vesicles?
herpes simplex
What are examples of flaccid vesicles?
pemphigus vulgaris
What are wheals?
irregularly shaped, elevated, edematous skin areas w/ well demarcated borders
What is excoriation?
superficial, often linear skin erosion caused by scratching
What is lichenification?
dry, leathery thickening of the epidermis w/ exaggerated/ increased skin markings; common in areas of folds
What is edema?
swelling due to accumulation of water in tissue
What are scales?
superficial epidermal cells that are dead and cast off from the skin
What is atrophy?
depression in the skin caused by the thinning of the epidermis or dermis
What does epidermal atrophy look like?
skin becomes transparent, loss of skin texture; cigarette paper like wrinkling, reveals the vessels below
What does dermal atrophy look like?
loss of connective tissue in the dermis, scar tissue; thinning associated w/ hypopigmentation
What is crust?
exudate of serum, blood, sebum or purulent material on the surface of the skin “scab”
What is ecthyma?
exudate that involves entire epidermis and accompanied by necrosis of deeper tissues
What is a fissure?
deep split in the skin extending into the dermis, sharply defined w/ vertical walls
What is erosion?
superficial, focal loss of part of the epidermis; heals w/o a scar
What is an ulceration?
focal loss of epidermis extending into the dermis or deeper tissue; heals w/ scar
What is a scar?
fibrous tissue that replaces normal dermal or subcutaneous tissue after skin injury
What is a hypertrophic scar?
do not exceed the margins of the original wound
What is a keloid?
scar extends into surrounding healthy tissue beyond the original wound; harder to manage
What is a comedone?
plug of sebaceous and keratinous material w/in the opening of a hair follicle
What is a milia?
small, 1-2 mm subepidermal keratin cysts that arise from pilosebaceous units or eccrine sweat ducts; hard and fixed
What is a cyst?
circumscribed lesion w/ a wall and a lumen; may contain liquid, solid, or semisolid material
What is a burrow?
narrow, elevated, tortuous channel typically produced by a parasite
What is a linear lesion?
follows a line or specific dermatome
What is an annular lesion?
circular or round
What is a serpiginous lesion?
wavy-border or “snake” like appearance; subset of annular lesion
What are examples of an extensor surface?
elbow, knee
What are examples of a flexor surface?
antecubital fossa, popliteal fossa
What is an intertriginous lesion?
occurring w/in the fold of the skin
What is a Wood’s Lamp?
black light w/ a magnifying glass; used to help dx
What will dermatophytosis illuminate as under a Wood’s Lamp?
yellow/green
What will erythrasma illuminate as under a Wood’s Lamp?
coral
What will porphyria illuminate as under a Wood’s Lamp?
red/pink
What is a dermatoscope?
hand lens w/ built-in lighting and a magnification of 10x to 30x used to see deeper layers not visible to the naked eye
What is diascopy?
special test performed by firmly pressing a microscopic slide over a skin lesion; used to assess erythema vs purpura
What is a Tzanck Smear?
simple, rapid inexpensive test utilized to dx HSV or causes of blistering skin conditions (SJS)
When would you expect to see multi-nucleated cells on a Tzanck smear?
pts w/ Herpes Zoster
What is a KOH prep?
simple method to microscopically identify fungi or yeasts from epidermal skin scrapings, hair roots, or nail clippings
What is patch testing?
dx aid for allergic contact dermatitis
What is photopatch testing?
type of patch test used when contact allergy is suspected that only occurs w/ exposure to sunlight
What is skin prick testing?
allergy test used to identify allergens responsible for triggering sx in Type 1 allergic rxns
What do you need to monitor for when performing a skin prick test?
anaphylaxis
What is acetowhitening?
performed using acetic acid (white vinegar) w/ colposcopy to detect subclinical HPV lesions; + result = blanching/whitening of lesion
What is a skin biopsy?
removal of a sample of skin to identify pathology; can shave, punch, or excision
What are the key questions to ask regarding a pts hx of skin lesions?
Onset, Location, Symptoms, Progression, Evolution, Provocative factors, Previous tx or alleviating factors
What are the ABCDEs of evaluating skin lesions?
Asymmetry, Border, Color, Diameter, Evolving
What 6 key features need to be documented regarding skin lesions?
Primary morphology, Size, Demarcation, Color, Secondary morphology, Distribution
What is the oKoebner phenomenon?
appearance of new skin lesions on previously unaffected skin secondary to trauma
What is the Auspitz sign?
slight scratching or curetting of a scaly lesion reveals punctate bleeding points w/in the lesion; common in psoriasis
What is the Nikolsky phenomenon?
epidermis is dislodged from the dermis by shearing pressure w/ a finger (SSS, TEN, pemphigus vulgaris)
What is the Darier sign?
rubbing or scratching the area of skin affected by mastocytosis results in a redness, swelling, itching, and a palpable wheal
Note
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