dermatology Flashcards
four primary causes of acne
hyperkeratosis
sebum overproduction
propionibacterium acnes proliferation
inflammation
epithelial cell junction that connects epithelial cells to the BM
hemidesmosomes
what is this skin disorder?
pruritus associated with asthma or allergic rhinitis
atopic dermatitis (eczema)
what is this skin disorder?
allergy to nickel
allergic dermatitis
what is this skin disorder?
parakerototic scaling
psoriasis
parakerototic scaling: nuclei still in stratum corneum + thickening of stratum corneum
caused by HPV type 2 and 4
common warts (verrucae)
layers of the epidermis
Come’on Lets Get Sun Burnt
C - stratum Corneum (keratinocytes)
L - stratum Lucidum
G - stratum Granulosum
S - stratum Spinosum (keratinocytes in SS connected by spines = desmosomes)
B - stratum Basale (stem cells + melanocytes here)
skin cell that: produces melanin responsible for skin/eye/hair color originate from neural crest cells located in stratum basale
melanocytes
what is located in the dermis?
blood vessels
pinpoint bleeding spots from exposure of dermal papillae (vessels here) when scales scraped off is a clinical feature of
psoriasis (called Auspitz sign)
cell that has the following roles:
makes collagen (part of ECM), glycosaminoglycans, reticular + elastic fibers, glycoproteins
provides STRUCTURAL integrity
important role in wound healing: secretes backbone of CT
stimulated by tissue damage
fibroblasts
protein found in hemidesmosomes
integrins
bind to collagen + laminin in BM to maintain INTEGRITY of the basolateral membrane
autoantibodies to integrin in hemidesmosomes results in
bullous pemphigoid
BULLOous = BELOW
protein found in desmosomes
desmoglein
autoantibodies to desmoglein in desmosomes results in
pehmphigus vulgaris
epithelial cell junction that joins adjacent cell membranes and prevents diffusion of fluid (impermeable) across the paracellular space
tight junctions
protein found in tight junctions
claudins + occludins
epithelial cell junction that connects the actin cytoskeleton’s of adjacent cells using cadherins
located below tight junctions
adherens junctions
CADherins = Calcium dependent ADhesion proteins
epithelial cell junction that resists shearing using keratin
found in simple + stratified squamous + muscle tissue
desmosome
epithelial cell junction which makes a connexon: a channel protein that allows electrical + chemical communication between adjacent cells
found in cardiac cells: myocytes communicate electrical signal from SA node → AVnode →bundle of His →purkinje system
gap junction
soft, tan-colored cauliflower like papules
hyperkeratosis: ↑ thickness of stratum corneum
epidermal hyperplasia
koilocytosis
verrucae = common warts hands = vulgaris (HPV 2 and 4) genitals = condyloma acuminatum (HPV 6 and 11)
benign
arises from nevocytes (type of melanocyte)
↑ risk melanoma if congenital or atypical
melanocytic nevus
↑ melanin pigment with normal number of melanocytes
ephelis (freckles)
pruitic rash on skin flexures
rash worsens with scratching, in dry mo (winter), washing every day (Infant)
starts on face in infants → behind knees, antecubital fossa in adults
associated with atopic diseases: asthma + allergic rhinitis
atopic dermatitis (eczema)
type IV hypersensitivity reaction following exposure to allergen
pruritic, linear rash at site of contact
allergic contact dermatitis
nickel, poision ivy, neomycin
papules and plaques with SILVERY scaling on knees + elbows
parakaratosis (nuclei still in stratum corneum)
↓stratum granulosum
↑stratum spinosum
+ Auspitz sign
possible nail pitting, arthritis (1/3 patients)
psoriasis: overproduction of new skin cells
treatment for verrucae
salicylic acid - OTC
imiquimod: ↑IFN to fight virus
liquid N2 in office
treatment of psoriasis
moisturizers - emollient (oil based) topical: normalize skin cell production →↓ inflammation steroids tar cream vitamin D analogs retinoids phototherapy oral: MTX, cyclosporine (rebound flaure after finish - not given often), retinoids
treatment for atopic dermatitis (eczema)
mild: moisturizing soap + emollient (oily)
mild-mod: calcineurin inhibitors (tracolimus or pimecrolimus)
flares: topical steroids
open lesion: antibiotics (cover s. aureus + strep)
prevent itch: antihistamines
if also have asthma/allergic rhinitis: LK inhibitor
UV light therapy
severe case/major flare: systemic steroids (short term)
very severe case (drugs of last resort): MTX, cyclosporine, azathioprine
treatment for acne due to hyperkaratosis
vitamin A analogs, such as:
topical: retinoic acid, tretinoin
oral: isotretinoin
treatment for acne due to sebum overproduction
isotretinoin
spironolactone (aldosterone antagonist: antiandrogen →↓cortisol, testosterone)
OCPs
treatment for acne due to propionibacterium acnes proliferation
oral antibiotics: erythromycin tetracycline doxycycline minocycline topical: clindamycin benzoyl peroxide (DOC of acne): ↓ bacterial growth
treatment for acne due to inflammation
steroids
flat, greasy, pigmented lesion with “stuck on” or “tortoise shell” appearance
seborrheic keratosis
benign flat, greasy, pigmented with squamous epithelial proliferation with KERATIN-FILLED CYSTS (horn cysts) in elderly
seborrheic keratosis
sudden appearance of multiple seborrheic keratoses
Leser-Trelat sign
underlying malignancy: GI, lymphoid
normal melanocyte number
↓ melanin production
albinism
↓ melancoyte number
vitiligo
↓tyrosine activity or defective tyrosine transport → ↓ melanin production
albinism
autoimmune destruction of melanocytes → complete depigmentation
vitiligo
stimulation of melanocyte → hyperpigmentation
well-demarcated macules
associated with pregnancy “mask of pregnancy”, OCP, HRT
resolves in mos.
melasma
honey-colored crusting near lips/nose of kid
S. aureus or S. pyogenes
very contangious
impetigo
treatment of impetigo
mild: topical mupirocin
severe: oral dicloxacillin or cephalexin (1st gen cephalosporin)
painful, rapidly spreading infection of dermis and suq tissue
S. aureus or S. pyogenes
usually due to break in skin or another infection
cellulitis
treatment of cellulitis
non-MRSA (non-purulent): oral dicloxacillin or cephalexin
MRSA (purulent): TMP-SMX or clindamycin
tender beyond visible area of infection
rapidly spreading celluitis along fascia plane
subq crepitus due to methane + CO2 from aneorbic bacteria
aneorobic bacteria or S. pyogenes (group A strep)
necrotizing fasciitis
“flesh eating bacteria”
treatment of necrotizing fasciitis
immediate surgical debridement to open pressure
IV carbapenem + clindamycin
exotoxin A + B destroy keratinocyte attachments in stratum granulosum
staphylococcal scalded skin syndrome
caused by S. aureus
fever + generalized erythematous rash
SLOUGHING of upper layers of epidermis
heals completeley
newborns + children
staphylococcal scalded skin syndrome
white plaques on tongue
CAN’T be scraped off
hairy leukoplakia
white plaques on tongue
EBV mediated infection in immunocompromised (HIV +)
5-25% are precancerous lesions
hairy leukoplakia
destruction of epidermal-dermal junction
toxic epidermal necrolysis
treatment of SSSS
cover s. aureus:
nafcillin
oxacillin
vancomycin
separation of epidermis upon manual stroking of skin
+ Nikolsky sign (pemphigus vulgaris)
very severe chronic autoimmune skin disorder
painful, flaccid (wrinkly) bullae caused by acantholysis (separation of epidermal cells) due to autoantibodies against desmosomes
ORAL MUCOSA involved
+ Nikolsky sign
pemphigus vulgaris
IF: reticular pattern of antibodies around epidermal cells
pemphigus vulgaris
tense blisters containing EOSINOPHILS
NO oral mucosa
- Nikolsky sign
bullous pemphigoid
IF: linear pattern at epidermal-dermal junction
bullous pemphigoid
pruritic vesicles associated with celiac disease
dermatitis herpetiformis
skin disorder associated with HIV
hairy leukoplakia
skin disorder associated with hepatitis C
lichen planus
pruritic papules due to deposits of IgA at tips of dermal papillae
worse with gluten intake
dermatitis herpetiformis (not due to HSV infection)
blistering skin disorder following an infection or drug reaction
pruritic
multiple lesions present: macules, papules, vesicles, target lesions
erythema multiforme
severe form of stevens-johnson syndrome with >30% of body SLOUGHING off
toxic epidermal necrolysis
fever + bulla + necrosis + SLOUGHING (separate epidermis from dermis)+ high mortality rate
hypersensitivity reaction to a drug
affecting skin + MUCOUS membranes
stevens-johnson syndrome
skin disorder with an ↑ risk of squamous cell carcinoma
actinic keratosis
thick scaly, crusty, sandpaper-like skin
premalignant lesions ( ↑ risk of squamous cell carcinoma)
cause by sun exposure (esp fair skinned)
actinic keratosis
treatment of actinic keratosis
5-FU
liquid N2
hyperpigmented, VELVETY thickening of skin (hyperplasia of stratum spinosum)
neck + axilla
hyperinsulinemia: diabetes, obesity, cushing syndrome
>40 yo: visceral malignancy (gastric adenocarcinoma)
acanthosis nigricans
> 40 yo with velvety rash on neck or axilla
acanthosis nigricans (with a visceral malignancy)
12-20 yo
painful, red, inflammatory lesion of subq (both shins)
associated with: sarcoidosis, coccidiodomycosis, histoplasmosis, TB, group A strep, leprosy
resolves in 3-6 wks
erythema nodosum
autoimmune skin disorder Pruritic Purple Polygonal Papules Plaques MUCOSA involved
5’Ps of lichen Planus
sawtooth infiltrate of lymphocytes at dermal-epidermal junction
lichen planus
“herald” patch on trunk or back → days later: multiple small patches along ribs (“christmas tree”) distribution
resolves in 6-8 wks
pityriasis rosea
thickened scar around face/chest
keloid
skin rash + proximal muscle weakness
dermatomyositis (associated with increase risk of malignancy)
rash on palms + soles
2° syphilis
rocky mountain spotted fever
coxsackie A virus
kawasaki disease (desquamation)
dermatologic findings in 1-3° syphilis
1°: painless chancre
2°: macuolopapular rash on palms + soles, condylomata lata
3°: gummas
acrodynia: peeling of finger tips
kowasaki disease
mercury poisioning
skin lesion due to bacillus anthracis
black eschar with necrosis surrounded by edematous ring caused by lethal factor and edema factor
