SKIN AND IT'S DISEASES Flashcards
What is treated in the realm of dermatology
anything that you can access without having to penetrate the body with a scope
What are the 3 layers of the skin
Epidermis
Dermis
Subcutaneous
What are the 4 major types of skin lesions
- Flat lesions
- Elevated lesions
- Fluid-filled lesions
- Other lesions
What are the two subtypes of flat lesions
- Macule - Small spot; not palpable, <1cm
- Patch - large spot not palpable, >1cm
What is a sun spot called
Lentigo
What are the two subtypes of elevated lesions
- Papule - small bump; superficial, elevated, < 1cm
- Plaque - Large bump; superficial, elevated, >1cm
What are the subtypes of a fluid-filled lesions?
- Vesicle - small bubble, fluid filled, usually superficial, <0.5 cm
- Bulla - Large bubble, fluid-filled, can be superficial or deep, >0.5
- Pustule - pus-containing bubble; often categorized according to whether or not they are related to hair follicles
What are the 4 Other lesions
- Scale
- Crust
- Excoriation
- Erosion
- Ulcer
What is a scale
Accumulation or excess shedding of keratin from the stratum corneum (uppermost layer of the epidermis) - flakey
What is a crust
Dried exudate (i.e. blood, serum, pus) on the skin surface; synonymous with scab
What is an excoriation
Loss of skin due to scratching or picking
What is an erosion
superficial open wound, loss of epidermis or mucosa only
What is an ulcer
deeper open wound with partial or complete loss of dermis or submucosa
do erosions heal with a scar
no
do ulcers heal with a scar
much more likely
What is the extent of injury and the appearance of a 1st degree burn
Superficial
Erythema (redness)
What is the extent of injury and the appearance of a second degree burn
Partial thickness
Blistering
What is the extent of injury and the appearance of a third degree burn
Full thickness
Necrosis
Why is the rule of 9s important
to know the extent of the burn - influences prognosis and management during first 48-72 hours
What are 4 types of chronic ulcers
- Pressure
- Vascular
- Neuropathic
- Other
What causes an arterial ulcer?
Poor inflow of blood into area
What causes a venous ulcer?
Blood not draining properly from limb - blood pules up in the extremity and changes hydrostatic forces in skin
What is the presentation + treatment of a venous ulcer
Above ankle, swollen
Want to compress limb
Do you want to compress an arterial ulcer
no - makes it worse
There must be damage to which skin layer in order to have scarring
dermis
What occurs if there is just superficial injury
blistering and erosions only - no scarring
What are the 3 phases of wound healing
- inflammatory
- proliferative
- remodelling
What occurs in the inflammatory stage? How long is it?
Involves vascular effects and a cellular response that culminates in acute inflammation which is aimed at eliminating pathogens or debris and delivering the materials required for healing the wound
24h - 2 weeks
What occurs in the proliferative stage? how long is it?
Production of materials to restore a functional skin barrier.
Days to months
Which layers of the skin need to be repaired during the proliferative stage
both the dermis and the epidermis
What occurs in the dermis during the proliferative stage
Fibroplasia (from fibroblasts) and neovascularization (from endothelial cells);
What does early angiogenesis and fibroplasia result in?
granulation tissue (Friable beefy-red tissue )
What occurs in the epidermis during the proliferation stage
the wound must re-epithelialize through keratinocyte proliferation and migration - Re-epithelialization from edges to cover up wound
What occurs during the remodelling phase? How long does it take?
The wound contracts and acquires increased tensile strength; the healed wound culminates in a scar
What is the classification of wounds and healing based on?
Time, extent, repair method
Acute or chronic
Partial or full thickness
Primary or secondary intention healing
What is the difference from partial thickness to full thickness wounds?
Partial thickness = epidermis and part of the dermis
Full thickness = extends through dermis and some of the subcutaneous layer or deeper
What is the difference between primary and secondary intention healing?
Primary - wound is completely closed by a surgical excision
Secondary - wound is left to completely heal on its own
What are two types of scars
Hypertropic scar
Keloid scar
What is a hypertropic scar
thick scar that is in excess of the amount of tissue required to replace the damaged dermis - thick and raise
What is a keloid scar
thick scar that clearly extends beyond the margins of the original wound
Are bacterial infections superficial or deep?
both
What are bacterial infections most commonly caused by
Streptococcus or Staphylococcus species
Are fungal infections more commonly superficial or deep? why?
superficial
Because causative organisms do not invade beyond the epidermis + they eat keratin and there is much less keratin inside the body
What are the two major types of superficial fungal infections
Dermatophytosis and candidiasis
How does dermatophytosis present itself
Look for scarly red rings
How does cadidiasis present itself
bright red patches and pustules (yeast infection)
what type of environment do fungal infections thrive in
moist and warm
How are infections by dermatophytes named
by the body side involved
Tinea _____
What are the most common herpes virus infections due to
Herpes simplex and varicella zoster
What is herpesvirus clinically characterized by
pain and that evolve to crusts
What is herpesvirus pathologivally characterized by
you get primary infection on skin - this will heal - but the virus will tract along sensory nerve to dorsal root ganglion in a dormant/latent phase forever. Causes pain because it is infecting the skin and the sensory nerve ending
What is the lay man terms for a primary varicella zoster and a secondary?
Chicken pox
Shingles
What is human papillomarvirus? What occurs with this virus
warts
Does not activate immune system but gets into cell and causes the epidermis to grow like crazy
How does malluscum contagiosum present
translucent papules with central keratotic core - white core you can squeeze out
What two populations is molluscum contagiosum common with
young children (correlated with swimming) Young adults (STD)
What are two types of infestations
scabies and lice
How does scabies present
intensely pruritic infestation; look for linear burrows on the skin
What are the five cardinal morphologic features of psoriasis vulgaris
- Plaque (raised lesions)
- Well-circumscribed margins
- Bright salmon red colour
- Silvery micaceous scale
- Symmetric distribution - bilateral
What is the pathogenesis of psoriasis
a chronic immunologic disease of the skin characterized by profound cutaneous inflammation and epidermal hyperproliferation
What is the prevalence of psoriasis
1-3% of population
with positive family history in up to 30% of patients
what are 5 complications seen with Psoriasis
- Physical - pruritus, fissuring, bleeding of lesions
- Emotional/psychological feel stigmatized and socially isolated; loss of self-esteem
- Economic - costs of medication; time away from work
- Severe psoriasis is associated w/ Increased risk of cardiovasculaar disease and shortened lifespan
- Psoriatic arthritis: 5-10% of patient with psoriasis will have psoriatic arthritis
How is Psoriasis treated
- Topical creams, oitments, gels, and lotions
- Physio w/ UV light
- Systemic therapy with immunosuppressive drugs such as methotrexate or cyclosporine
Eczema is clinically referred to
dermatitis
How does eczema (dermatitis) present?
Itchy, red, scaly disorders
Eczema (dermatitis) can be ___ or _____
endogenous (atopic dermatitis) or exogenous (contact dermatitis)
What is atopic dermatitis
comes from inside your body
- intensely pruritic inflammatory skin disorder associated with atopy: astham, hayfever, and allergic conjuctivitis
What is the most outstanding clinical feature of atopic dermatitis? What are some other presentations?
pruritis
Other:
- Marked xerosis (dry, scaly skin)
- Ill-defined erythema
- Tiny coalescing edamatous papules or papulovesicles
Lichenification (thickening of skin lines)
- Excoriation
- Crusting (if secondarily infected)
What is the treatment of atopic dermatitis
- Avoid irritating factors (alcohol containing agents)
- Aggressive restoration of the cutaneous permeability barrier with bland emolients and moisturizers
- Topical glucocorticoids
- Topical immunomodulators
- Topical or systemic anti-staphylococcal antibiotics
- Oral antihistamies
- UV phototherapy for severe or resistant cases
What are the two forms of contact dermatitis
- Allergic contact dermatitis: immune hypersensitivity to an allergen in contact with the skin
- Irritant contact dermatitis: Contact of the skin with something that primarily causes direct local irritation
What is seborrheic dermatitis
Where does it occur
Dandruff -
Areas of higher sebaceous gland activity
What causes seborrheic dermatits
excessive immune reaction to a lipophilic yeast called Pityrosporum that normally occurs on skin
What are two associated disorders with seborrheic dermatits
PD and immobility due to other neurological disorders
HIV infection
What are 3 autoimmune connective tissue disorders
- Lupus erythematosus
- Scleroderma/System sclerosis
- Dermatomyositis/Polymyositis
What are the skin findings of lupus erythematosus
Malar “butterfly rash”, localized erythema and edma, alopecia, photosensitivity, mucosal ulcers, Raynauds phenomenon
What occurs with scleroderma/system sclerosis
- Autoimmunity provokes a massive fibrotic tissue response
- Cutaneous fibrosis can be localized or widespread; may lead to joint contractures; Raynaud’s phenomenon
What are the systemic manifestations of scleroderma/system sclerosis
Hypertension, pulmonary fibrosis, GI dysmotility,
What is dermatomyositis/polymyositis
Autoimmune connective tissue disorder
Has inflammatory myosistis leading to muscle weakness
What is the difference between dermatomyositis and polymyosistis
derma = skin and muscle poly = just muscle
What are two types of benign skin tumors
- seborrheic keratosis
- Melanocytic nevi - moles
What are 3 types of skin cancer
- Basal cell carcinoma
- Squamous cell carcinoma
- Malignant melanoma
What do cells in basal cell carcinoma look like
- Basal layer of the epidermis
- Translucent skin-colored nodules
- May be eroded or ulcerated
What is basal cell carcinoma likely to spread to
not other organs but rather along surface of skin
What are the 3 types of basal cell carcinoma
- Nodular - big bump on skin
- Superficial - spreading on surface - flatter
- Sclerosing (looks like a scar)
what is the appearance of squamous cell carcinoma?
- Solid skin tumors
- May often be volcano-shaped
- Thick overlying scale
- Lots of keratin so not translucent in appearance
What is an actinic keratosis?
Describe its appearance
- Precursor lesion to squamous cell carcinoma
- Actinic Keratosis are scaly; skin coloured, pink or red and rough in texture
Are squamous cell carcinomas likely to spread to organs?
yes
What is the most dangerous form of skin cancer
Malignant melanoma - highest potential for spread to other organs
What is the least dangerous form of skin cancer
Basal cell carcinoma
What is the ABCDE rule for melanoma used for
for detection
What is the ABCDE rule for melanoma?
A= Asymmetry B = Border C = Colour D = Diamete E = evolving or eccentric
What are some major risk factors for skin cancer
- Prior personal history of skin cancer or pre-cancer
- Excessive prior sun exposure
- Presence of multiple skin moles
- Presence of abnormal looking moles
- Family history of skin cancer
- Chronic systemic immunosuppression
