Skin Diseases Flashcards
What is a macule?
flat discolored lesion less than 1 cm in diameter
What is a patch?
flat discolored lesion greater than 1 cm in diameter
What is a papule?
firm elevated lesion less than 1 cm
What is a plaque?
firm elevated lesion greater than 1 cm
What is a vesicle?
elevated, fluid-filled lesion less than 1 cm
What is a bulla?
elevated, fluid-filled lesion greater than 1 cm
What is a pustule?
vesicle or bulla that contains pus (not clear fluid)
What is a nodule?
firm elevated lesion (equal in diameter and in thickness)
What is an ulcer?
crater in skin (goes to epidermis, can go down to dermis)
What is a fissure?
small linear crack in skin
What lesion is equal in diameter and in thickness?
nodule
What lesion goes to the dermis and, in some cases, can also go down to the dermis?
ulcer
What is another name for contact dermatitis?
spongiotic or inflammatory dermatitis
What type of inflammatory cells are moving into the affected area in contact dermatitis?
lymphocytes
What type of cells are separating in the epidermis in contact dermatitis?
keratinocytes
Separation in the epidermis in pts with contact dermatitis is caused by what?
edema
What can severe edema cause in pts with contact dermatitis?
separation from dermis and epidermis
What does contact dermatitis look like under a microscope?
looks like a sponge (spaces between cells in epidermis)
What is contact dermatitis caused by? Give two examples:
skin coming into contact with allergen
ex: poison ivy / latex allergy
Describe contact dermatitis lesions:
localized, erythematous papules/pustules/vesicles and sometimes pustules
What type of hypersensitivity is contact dermatitis?
type IV hypersensitivity
How do you treat contact dermatitis?
topical corticosteroids
What is another name for psoriasis?
psoriasiform dermatitis
Psoriasis is an inflammatory disorder with epidermal ______.
thickening
Psoriasis is associated with what other inflammatory condition?
psoriasis arthritis
What percent of the population does psoriasis affect?
1-2% of the population
(possible genetic origin)
When is psoriasis typically manifested?
teenage years
What is the acute phase of psoriasis characterized by?
erythematous plaques
What is the chronic phase of psoriasis characterized by?
white with silvery scales
In the chronic phase of psoriasis, what causes the silvery scales?
epidermal thickening
Where is psoriasis typically found on the body?
scalp, trunk, extensor surfaces of arms/legs
What is the theory behind the cause of psoriasis?
- antigens stimulate an immune response
- T cells are activated
- increase of cytokines led to inflammation
- causes epidermal hyperplasia
NEGATIVE FEEDBACK LOOP
What are rete ridges commonly seen in histopathological images of psoriasis?
where the epidermis dips down
What is epidermopoiesis?
epidermal proliferation
Pt’s with psoriasis have how many more keratinocytes than someone with normal skin?
30x more keratinocytes
How long does it take for normal skin to shed?
2-3 weeks
In normal skin turnover, the cells of the stratum corneum are dead and lack what?
lack a nucleus
In psoriatic skin turnover, the cells of the stratum corneum have _____.
have nuclei
How long does it take for dead skin cells to surface in pts with psoriasis?
2-3 days
What is it called when cells of the stratum corneum have nuclei?
parakeratosis
Why do pt’s with psoriasis present with silvery scales?
because cell turnover is so fast and the skin cells haven’t shed yet
In pts with psoriasis, the endothelial cells become thickened. What does this cause?
dilated capillaries in dermis
What are the treatments for psoriasis?
- corticosteroids
- immunosuppressives (methotrexate)
- biologics
What are two biologics that are used to treat psoriasis?
Humira and Otezla
Urticaria is commonly known as what?
hives
What type of hypersensitivity is urticaria?
Type I hypersensitivity
What are two skin diseases that are histamine related?
urticaria and atopic dermatitis
What type of lesions present with urticaria?
erythematous papular lesions (sometimes macular lesions)
Urticaria causes histamine to be released, what does this cause?
- vasodilation and increased capillary permeability
- stimulates nerve endings
What is a result of increased capillary permeability in pts with urticaria?
- pruritus (inc. cap. perm. stimulates nerve endings)
- vascular leasions
Urticaria is primarily caused from:
- ingested foods (shellfish / peanuts)
- medications
What type of dermatitis is lichen planus?
interface type of dermatitis (between epidermis and dermis)
Describe the lesions of lichen planus:
violet/purple papular lesions
What type of reaction is lichen planus?
cell mediated immune reaction
What is a cell mediated immune reaction?
where damage to keratinocytes occurs
Lichen planus can be a result of some medications. Give an example of two of these medications:
- Therapeutic gold (for arthritis)
- Antimalarials (Plaquenil)
What type of cell infiltration occurs at the epidermis/dermis border of lichen planus?
lymphocytic infiltration
What are the white areas in lichen planus?
keratinocytes dying and leaving spaces at border
In lichen planus, what happens in the epidermis where keratinocytes used to be?
vacuolation (formation of vacuoles)
Cells with necrotic keratinocytes can be seen in histological images of what skin disease?
lichen planus
Necrotic keratinocytes are also called what?
colloid bodies
Atopic dermatitis is also known as what?
eczema
What type of hypersensitivity is atopic dermatitis?
type I hypersensitivity
Atopic dermatitis in adults becomes hard, what is this called?
kinofied
What two things will you see increased in blood work of a pt with atopic dermatitis?
increased eosinophils and IgE
What is a common trigger for eczema (atopic dermatitis)?
change in temperature/humidity
What are some treatments for eczema?
- topical corticosteroids
- sometimes histamines
- biologics (dupixent)
What biologic treats atopic dermatitis?
dupixent
What type of dermatitis is bullous pemphigoid?
a type of vesiculobullous dermatitis
What type of disease is bullous pemphigoid?
autoimmune disease (produces Ab against Ag in basement membrane)
Epidermal cells hold onto basement membranes via junctions. What are these junctions called?
hemidesmosomes
What are within hemidesmosomes?
antigens
What happens to the skin in bullous pemphigoid? (hint: two things)
- epidermis separates from dermis completely
- dermal cells separate from basement membrane
Where do blisters occur in bullous pemphigoid?
oral mucosa, extremities, lower trunk
What proves IgG is produced against basement membranes in bullous pemphigoid?
immunofluorescence
What is the treatment for bullous pemphigoid?
Prednisone (corticosteroid)
What causes scleroderma?
IDIOPATHIC (but probably autoimmune disease)
What is scleroderma?
systemic disease of abnormal collagen deposition
Where is collagen deposited in scleroderma?
in blood vessels
What occurs as a result of collagen deposits in blood vessels in a pt with scleroderma?
- decrease in blood vessel diameter
- decrease blood flow to organs in body/skin
What is fibrosis and what happens when skin becomes fibrotic?
- fibrosis = excessive collagen in dermis
- skin becomes tight = pts unable to move fingers
In severe cases of scleroderma, what happens?
can affect pt’s mouth/eyes (won’t be able to move them)
Leukocytoclastic vasculitis (LCV) is an inflammatory process of what?
blood vessels
What is one manifestation of systemic disease in pts with leukocytoclastic vasculitis (LCV)?
skin
What is a trigger that causes leuokocytoclastic vasculitis in pts?
infection or medication
Describe the inflammatory process of leukocytoclastic vasculitis:
- Ab binding to Ag forms immune complex
- complex sits in blood vessel walls
- cascade of complement system occurs
- complement causes infiltration of inflammatory cells
What is attacked first in leukocytoclasic vasculitis (LCV)?
venules
What is the most permeable blood vessels we have?
venules
What causes the reddish brown papular lesions in leuokocytoclasic vasculitis?
inflammatory cells & fibrin leak out and separates epidermis from dermis
What is the treatment for leukocytoclastic vasculitis?
corticosteroids
What is cellulitis?
bacterial infection of dermis and hypodermis
What can cellulitis sometimes look like?
DVT
Describe cellulitis:
deep reddish color, warm to tough, very painful
What does erysipelas mean?
bacterial infection of upper demis
What are furuncles?
boils (red elevated nodule)
Furuncles are an infection of what?
hair follicle
What is cellulitis caused by?
staph aureus or strep
What is impetigo caused from?
staph aureus or group A strep
Impetigo is common in who? Is it contagious?
in children, very contagious
How does impetigo start out as?
little vesicles
The brown crusted lesions in pts with impetigo are formed how?
from ruptured little vesicles (very itchy)
How do you treat impetigo?
topical abx
What is acute necrotizing fasciitis?
flesh eating disease
Acute necrotizing fasciitis is primarily due to what?
group A strep, especially staph pyogenes
How does acute necrotizing fasciitis usually start?
starts as minor trauma or simple infection
T/F acute necrotizing fasciitis goes down to epidermis
FALSE: goes down to epidermis AND dermis
Acute necrotizing fasciitis can go down to subcutaneous tissue and fascia around muscles. What does this cause?
- fascia becomes edematous
- blocks small blood vessels
- cuts off blood supply = can cause tissues to die
What can acute necrotizing fasciitis sometimes look like?
cellulitis
What symptoms can a pt develop if they have acute necrotizing fasciitis?
- fever
- hypotension
- tachycardia
= can lead to toxic shock
How do you treat necrotizing fasciitis?
find out what bacteria is toxic
- topical abx, fluids, decried necrotic tissue
What might need to happen if debridement of necrotic tissue becomes too much?
amputation
Why does necrotizing fasciitis get so severe so quickly?
because no one recognizes the symptoms of the flesh eating disease
What is the mortality rate of necrotizing fasciitis?
20-30%
What type of reaction is erythema nodosum and what does it involve?
panniculitis type of rxn = involves subcutaneous fat
What type of hypersensitivity is erythema nodosum?
delayed-type of hypersensitivity
What can trigger erythema nodosum?
stress, IBS, estrogen oral contraceptive
Who is erythema nodosum most common in?
3x more common in women
What becomes thick due to an inflammatory process in erythema nodosum?
septa between lobules of fat
Where can you find lesions in pts with erythema nodosum?
anterior aspect of lower extremities
Describe the lesions of erythema nodosum:
firm, painful reddish-brown nodules
Where does herpes simplex virus remain latent?
in sensory ganglion of the trigeminal nerve
Where is herpes simplex virus present?
saliva
What is the biggest tigger for herpes simplex virus?
stress!! sometimes pts can feel it coming on (will feel pain and tingling before flare up)
How do you treat herpes simplex?
- acyclovir (zovirax)
- docosanol (abreva - over the counter)
- valacyclovir (valtrex)
What is varrucae?
warts produced by HPV 1-4
Where do plantar warts grow?
grows on plantar aspect of interior foot
How do you treat verrucae?
topical meds, liquid nitrogen, surgery
What is tinea capitis and who is it common in?
fungal infection of scalp (common in children)
What happens to the scalp in tinea capitis?
hair loss and scalp becomes erythematous
What type of lesions are seen on the scalp in tinea capitis?
scaling lesions
What is tinea capitis caused by?
- microsporum canis (found in dogs)
- tricophyton tonsurans
What is the treatment of tinea capitis?
oral anti fungal = Gris-peg (griseofulvin)
What is another name for tinea corporis?
ringworm
Describe the lesions of tinea corporis
erythematous papular lesions (sometimes vesicles)
What fungal infection is characterized by a clear center that is very itchy?
tinea corporis
What is the treatment for tinea corporis?
topicals = Nizoral (ketoconazole)
What is another name for tinea pedis?
athlete’s foot
What is tinea pedis caused by?
tricophytan
Where is tinea pedis commonly found?
in warm/damp areas (communal pools/showers)
What is the treatment for tinea pedis?
topicals = Tinactin (tolnaftate)
What is another name for tinea unguium?
onchomycosis
What is tinea unguium?
fungal infection of nails (common in warm climates)
What is scabies caused by?
sarcoptes scabieuse mite
(female mite that infects humans)
What do the light brown lines indicate in a pt with scabies?
burrows with vesicles
Why does the skin itch and become inflamed in pt’s who have scabies?
feces, as larvae move through skin
Where is scabies typically found and commonly spread?
- found in warm/closed up body parts (elbow, waist, neck)
- commonly spread in bed linens
What is the treatment for scabies?
Gammallin (topical lindane)
What is another name for pediculosis?
lice
What is pediculus humanus corporis?
Body nits
What is pediculus pubis?
pubic nits
What is pediculus humanus capitis?
Scalp nits
Where does lice feed in pt’s with pediculosis?
feed on blood in scalp
What causes the scalp to become itchy in pediculosis?
saliva of lice reacts with skin = itching
What is the treatment for lice?
Nix (topical permethrin)
Acne is an inflammatory reaction against what?
folliculo sebaceous glands
Describe acne lesions, where it is commonly found, and who does it affect most?
- papular, pustules
- found on face, neck, chest, back
- affects teens (puberty)
What percent of people ages 40-50 will have acne?
3-5%
How does acne occur?
keratin plug in hair follicle (when ruptured, causes inflammatory reaction)
The inflammatory reaction in acne is caused by what cells?
lymphocytes
What is a commensal bacteria in pt’s with acne that increased when excess sebum is available?
propionibacterium acnes
What is the most common skin CA?
basal cell
Describe what basal cell CA looks like:
shiney, papule, center becomes ulcerated
Where does basal CA metastasize to?
slowly into dermis
What is the second most common form of skin CA?
squamous cell
Describe squamous cell CA:
scaly, erythematous, raised lesions with irregular borders
Where can malignant melanoma originate from?
- melanocytes in epidermis
- collection of melanocytes like a mole
What is a nevus?
a mole
What skin CA has the worst prognosis?
malignant melanoma
What are 4 basic categories of melanoma?
- superficial spreading
- lentigo melanoma
- sacral lentigimous
- nodular melanoma
What is melanotic melanoma?
cancer of melanocytes that don’t produce melanin
What is the 5 year survival rate of melanoma? What has contributed to this?
- 99% survival rate if diagnosed before metastasis
- pt education and counseling
What cancer is second to leukemia to # of young lives lost?
malignant melanoma
What is the ABCDE method and what is it used for?
used for diagnosing malignant melanoma
A - asymmetry
B- border irregularity
C - color (multiple)
D - diameter (more than 6 mm)
E - evolution (how its changed over time)