Derm Intro Flashcards
Dermatology visits account for _____% of all outpatient visits annually.
> 10%
List 6 functions of the skin.
PASSER
- protection
- absorption
- secretion
- sensation
- excretion
- regulation
What are the 3 major layers of the skin? (Think very basic.)
- epidermis
- dermis
- subcutaneous fat
Characteristics of the Epidermis
- sloughs off
- waterproofing
- contains melanocytes –> discoloration, sunburns
- replaced every 30 days
Characteristics of the Dermis
- basement membrane
- hair follicles, sweat glands, vasculature
- provides skin strength and elasticity: prevents splitting of skin and foreign invasion
Characteristics of Subcutaneous Fat
- insulation –> heat
- cushioning
- smooths and contours the skin: deep injury and scarring can mean the skin will not repair as smoothly
Describe primary flat lesions.
Name the different types.
How do you differentiate between them?
- circumscribed flat area of discoloration without elevation and depression (non-palpable)
- macule: < 1 cm, eg freckle
- patch: > 1 cm, eg birthmark
Name and describe the one type of primary raised lesions.
- plaque
- well-circumscribed
- elevated
- superficial
- solid
- > 1 cm diameter
- may be formed from confluent papules
Describe primary raised solid lesions.
Name the different types.
How do you differentiate them?
- circumscribed, elevated/palpable, solid lesion
- papule: < 1 cm
- nodule: > 1 cm; usually found in dermal or SQ tissue; may be above, level with or beneath skin surface
- tumor: > 2 cm; aka “mass”; can be above, level with or beneath skin surface
Describe primary raised filled lesions.
Name the different types.
How do you differentiate them?
- small, superficial, circumscribed elevation of the skin
- vesicle: < 0.5 cm w/ serous fluid
- pustule: < 1 cm w/ purulent material (WBCs or pus); can be sterile or infected; eg zit
- bulla: > 0.5 cm w/ serous fluid; eg blister
Primary Raised Lesion: Wheal
- transient (comes and goes)
- circumscribed, elevated papules or plaques
- often with erythematous borders and pale centers
- eg hives, TB test
Purpura
- non-blanching (red color doesn’t fade to white w/ pressure)
- violaceous (red-purple) discoloration of skin
- may be palpable or non-palpable
- is due to blood that extravasates outside vessel walls
- non-palpable types: petechiae (5 mm)
- Primary Lesion
2. Secondary Lesion
- develop from disease process/condition; first basic skin change that is unchanged by outside forces
- modifications of primary lesions due to natural course of disease, itching, infection, other factors
Scale
- visible shedding of stratum corneum (epidermal layer)
- eg skin peeling w/ sunburn
Crust
-dried exudate (could have been serous, purulent or hemorrhagic –> any sort of fluid that has dried on the skin)
Erosion
- loss of superficial layers of upper epidermis
- due to wearing away from friction or pressure
- red
- oozes/weepy
Ulcer
- localized defect of irregular size and shape
- loss of epidermis and some dermis
- scars
Fissure
- sharply-defined, linear or wedge shaped tears in epidermis
- abrupt walls
- skin very dry –> encourage patients to keep skin away from water and use emollients
- can have bleeding if deep enough into dermis
- eg cracked heels
Excoriations
- skin abrasions
- usually superficial due to scratching of skin
- ice packs on itchy skin helpful
Lichenification
- thickening of epidermis
- results in accentuation of skin lines
- due to excessive excoriations
Scar
- final stage of healing which involved deeper dermis
- hypertrophic: any scar that goes beyond expected borders
- keloidal: very excessive, overgrown scar; some people are more prone to keloids –> removal can make it worse
Atrophy
- thinning or depression of skin due to reduction of underlying tissue
- can happen w/ weight gain (eg pregnancy or body builders)
- eg stretch marks
Sclerosis
- hardening/induration of the skin
- caused by increase in collagen, other CT components (mucin), edema, or cellular infiltration
Necrosis
- death of skin tissue
- usually black in color
- MUST be removed from body
Comedone
- darkened plug of sebum and keratin
- occludes pilosebaceous follicles
- can be open (black head) or closed (white head)
Cyst
- encapsulated, raised lesion
- filled with solid or liquid material
- often fluctuant: if you push, the fluid can displace and “give in”
- skin cyst different than cyst on an organ
Burrow
- linear or serpiginous (snake-like) tunnels within the epidermis
- eg mites, scabies
Telangiectasia
- dilated, superficial blood vessels
- small but visible
- often happens with excess sun exposure
- eg spider veins
Xerosis
dry skin
Pigmentation
- change in intensity of the brown colors (melanin) normally inherent in skin
- hyper or hypopigmentation
Poikiloderma
- combo of cutaneous pigmentation, atrophy and telangiectasia
- produces a mottled appearance of skin
- common with DM
Define distribution.
Give some examples of the distribution of derm conditions.
- location on the body, eg head, torso, etc
- random, symmetric, flexures vs extensors, exposed vs intertriginous (skin on skin) sites, sites of pressure, photo-distributed vs non-sun exposed, acral (palms and soles)
Configuration Arrangement Types:
- Discrete
- Confluent
- each lesion easily separated from the others
2. edges of the lesions blend into one another
Configuration Arrangement Types:
- Isolated
- Scattered
- Grouped
- just one lesion in an area
- lesions are discrete, multiple and distributed in no discernible pattern
- lesions appear close together with normal skin between groups
Configuration Arrangement Types:
- Linear
- Dermatomal
- in a line
2. distributed in one spinal nerve or spinal nerve equivalent branch; eg herpes zoster (shingles)
Configuration Shape Types:
- Annular
- Polycyclic
- ring-like, circular
2. shape made up of tangential rings
Configuration Shape Types:
- Arcuate
- Serpiginous
- arc or crescent shaped
2. shaped like a snake
Configuration Shape Types:
- Iris/target
- Reticulate
- Glaborous
- shaped like a bulls-eye (eg Lyme disease)
- net-like, lacy pattern
- shiny and smooth surface; bald
Why would finding a dermatological condition on an acral surface be important?
- acral is palms of hands or soles of feet
- very few derm. things happen here so it narrows down differential diagnosis quickly
Why would family history be important for a dermatology patient?
-important for determining autoimmune nature of some derm conditions
What characteristics might be used to describe a lesion?
- location/distribution on the body
- number: single? 4? several?
- size/shape
- color
- texture
- configuration: pattern and arrangement
- surrounding skin (eg erythema)
- borders
What is important to take into account when making a derm. diagnosis?
- age
- lesion distribution, characteristics
- under and overdiagnosis
- race
- need for referral
- confirmatory procedures
- “common things are common”: top 50-100 diagnoses
Elliptical Excision
- anesthetize
- excise in elliptical shape with length 3x the width
- undermine edges (separate dermis and epidermis) to suture without puckering
Shave Biopsy/Excision
- anesthetize and make a wheal around lesion
- excise in scooping manner to get underlying dermis/SQ
Punch Biopsy
- anesthetize
- place punch 90 degrees to skin and rotate with downward pressure until reaching SQ
- lift gently and cut bottom
What is a KOH procedure used for?
- scrape the scaly lesion and add KOH to slide
- helps determine if it is a fungal infection –> spores, hyphae, budding
What is a Tzanck smear used for?
- “unroof” an intact vesicle at the base and collect fluid on swab
- used to confirm herpes or varicella infection
Dermoscopy
-can help determine benign vs malignant by magnifying algorithmic patterns
Wood’s Light
- shine light on skin to see some organisms that will glow under black light
- coral/pink: erythrasma
- pale blue: Pseudomonas
- yellow/green: Microsporum
- green/gold: tinea versicolor
- white: vitiligo
