bananas's version from 2015-05-25 15:24


Epidermal layers and junctions:
Question Answer
What are the layers of the epidermis, from top to bottom?Stratum Corneum, Lucidum, Granulosum, Spinosum, Basale
[California likes Girls in String Bikinis]
What is found in the Stratum Corneum?Keratin
What cell junction is found in the Stratum Spinosum?Desmosomes
What is found in the Stratum Basale?Stem cells
What infection affects the Stratum Granulosum?Staphylococcus Scalded Skin
Tight junctions are composed of [?]Claudins and Occludins [aka Zonula occludens]
What do the tight junctions do?Impermeable to water: prevent solute movement
Adherens junctions are composed of ?CADherins (Ca++ Dependent ADhesion molecules)
[Rhymes with Adherens]
What do adherens junctions do?"Belt" connecting actin cytoskeletin of adjacent cells
Loss of [?] promotes metastasisE-cadherin
(Ex. Lobular carcinoma)
What do the desmosomes do?Cell-Cell adhesion
Structural support via keratin interactions
Desmosomes are made of [?]Desmoglein
Desmosomes are targeted in what dermatologic disease?Pemphigus Vulgaris: autoantibodies against Desmoglein
[DAMN is a Vulgar word]
What do gap junctions do?Allow electrical and chemical communication between cells
Gap junctions are made of [?]Connexon channel proteins
What do hemidesmosomes do?Connect keratin to basement membrane
Hemidesmosomes are made of [?]Integrins: membrane proteins that bind to collagen and laminin in the basement membrane
Hemidesmosomes are targeted in what dermatologic disease?Bullous Pemphigoid
[Bullous is down bullow]

Macroscopic terms

Question Answer Column 3
MaculeFlat lesion with well-circumscribed change in skin color < 5mmFreckle, labial macule
PatchMacule > 5mmLarge birthmark (congenital nevus)
PapuleElevated solid skin lesion < 5mmMole (nevus), acne
PlaquePapule > 5Psoriasis
VesicleSmall fluid-containing blister < 5mmChickenpox, shingles
BullaLarge fluid-containing blister > 5mmBullous pemphigoid
PustuleVesicle containing pusPustular psoriasis
WhealTransient smooth papule or plaqueHives (urticaria)
ScaleFlaking off of stratum corneumEczema, psoriasis, SCC
CrustDry exudateImpetigo

Microscopic terms

Question Answer Column 3
Hyperkeratosis↑ thickness of stratum corneumPsoriasis
ParakeratosisHyperkeratosis with retention of nuclei in stratum corneumPsoriasis
AcantholysisSeparation of epidermal cellsPemphigus vulgaris
AcanthosisEpidermal hyperplasia (↑ spinosum)Acanthosis nigricans
DermatitisInflammation of the skinAtopic dermatitis

Skin disorders (Common, blistering)

Question Answer
Albinism↓ melanin production d/t ↓ tyrosinase activity (normal # of melanocytes)
Neural crest cell fail to migrate during development
Melasma (chloasma)Hyperpigmentation assoc w pregnancy or OCP use
"mask of pregnancy"
VitiligoIrregular areas of complete depigmentation
Caused by a ↓ in melanocytes
VerrucaeWarts - caused by HPV
Epidermal hyperplasia, hyperkeratosis, koilocytosis
Condyloma acuminatum on genitals
Melanocytic nevusCommon mole. Melanoma can arise from congenital or atypical moles
Intradermal nevi are papular
Junctional nevi are flat macules
Pruritic wheals that form after mast cell degranulation
Normal number of melanocytes, ↑ melanin pigment
Atopic dermatitis (eczema)Pruritic eruption, commonly on skin flexures
Assoc with Asthma, Allergic rhinitis
Starts on the face in infancy, later in Antecubital fossa
Allergic contact dermatitisType 4 hypersensitivity rxn
(nickel, poison ivy, neomycin)
PsoriasisPapules and plaques with silvery scaling, esp on knees and elbows
Acanthosis with parakeratotic scaling (nuclei still in stratum corneum)
↑ stratum spinosum, ↓ stratum granulosum
Auspitz sign - pinpoint bleeding spots when scales are scraped off
Assoc w nail pitting and psoriatic arthritis
Treat with Vitamin D analogs: Calcipotriene, Calcitriol, Tacalcitol
Seborrheic keratosisFlat, greasy, pigmented squamous epithelial proliferation
Keratin-filled cysts (horn cysts)
Looks "stuck on"
Lesions on head, trunk, extremities
Common benign neoplasm of older persons
Leser-Trelat signSudden appearance of multiple seborrheic keratoses, indicates an underlying malignancy (GI, lymphoid)
Pemphigus vulgarisDesmosome targeted by autoimmune IgG against Desmoglein 3
Acantholysis - intraepidermal bullae causing flaccid blister involving the skin and oral mucosa
Nikolsky's sign - separation of epidermis upon manual stroking of skin

[DAMN is a vulgar word]
Bullous pemphigoidAutoimmune disorder with IgG antibody against hemidesmosomes (epidermal BM)
Linear immunofluorescence
Eosinophils within tense blisters
Spares oral mucosa
Negative Nikolsky's sign - skin doesn't fall off when you stroke it
Dermatitis herpetiformisPruritic papules, vesicles, and bullae on extensor surface
IgA deposits/neutrophils at tips of dermal papillae
Assoc with Celiac disease
Erythema multiformeInfections - Mycoplasma pneumoniae, HSV
Drugs - sulfa, β-lactams, phenytoin
Autoimmune diseases
Multiple types of lesions: macules, papules, vesicles, target lesions
Stevens-Johnson syndromeFever, bulla formation and necrosis, sloughing of skin, and a high mortality rate
2 mucus membranes are involved (eyes, mouth, etc) - lesions may appear like targets
Assoc w adverse drug rxn [CLAPPERS]
Toxic epidermal necrolysisSevere Stevens-Johnson syndrome > 30% of the body surface area
Which drugs cause SJS?Carbamazepine, Lamotrigine, Allopurinol, Phenytoin, Phenobarbital, Penicillin, Ethosuximide, RASH, Sulfa drugs [CLAPPPERS]

Skin disorders (Misc. and infectious)

Question Answer
Acanthosis nigricansEpidermal hyperplasia causing symmetrical, hyperpigmented, velvety thickening of skin on neck or armpits
Assoc w hyperinsulinemia (diabetes, obesity, Cushing's syndrome)
visceral malignancy
polycystic ovary disease
Actinic keratosisPremalignant lesions caused by sun exposure
Small, rough, erythematous or brownish papules or plaques
Risk of squamous cell carcinoma is proportional to degree of epithelial dysplasia
Erythema nodosumInflammatory lesions of subcutaneous fat, usually on anterior shins
Assoc w
streptococcal infxns
Crohn's disease
Lichen PlanusPruritic
Polygonal Planar Papules and Plaques
Sawtooth infiltrate of lymphocytes at dermal-epidermal jct
Assoc w Hep C
Pityriasis rosea"Herald patch" first (2-10 cm rash on chest) followed days later by "Christmas tree" distribution
Multiple plaques with collarette scale
Self-resolving in 6-8 weeks
SunburnUV irradiation → DNA mutations → apoptosis of keratinocytes
UVA - tanning and photoaging
UVB - sunburn
Can lead to impetigo and skin cancers (Basal cell, squamous cell, and melanoma)
ImpetigoVery superficial skin infections
Staph a or Strep pyogenes
Highly contagious
Honey-colored crusting
Bullous impetigohas bullae and is usually caused by Staph a
CellulitisAcute, painful, spreading infxn of dermis and subQ tissues
Usuall Strep pyogenes or Staph a
Starts with a break in skin from trauma or other infxn
Necrotizing fasciitisDeeper tissue injury - anaerobic bacteria or Strep pyogenes
Crepitus from methane and CO2 production
"Flesh-eating bacteria"
Bullae and purple color
Staphylococcal scalded skin syndrome (SSSS)Exotoxin destroys keratinocyte attachments in stratum granulosum only (vs toxic epidermal necrolysis which destroys epidermal-dermal jct)
Fever, generalized erythematous rash w sloughing of upper layers - heals completely
Newborns and children
Hairy leukoplakiaWhite, painless plaques on tongue - cannot be scraped off
EBV mediated
Occurs in HIV positive pts

Skin cancer

Question Answer
What is the most common skin cancer?Basal cell carcinoma
Locally invasive but never metastasizesBasal cell carcinoma
Pink, pearly nodules w rolled borders and central crusting or ulcerationBasal cell carcinoma
Commonly with telangiectasiasBasal cell carcinoma
nonhealing ulcers with infiltrating growthBasal cell carcinoma
scaling plaqueBasal cell carcinoma
Palisading nucleiBasal cell carcinoma
Second most common skin cancerSCC
Arsenic exposureSCC
Commonly on face, lower lip, ears, and handsSCC
Maybe LNs, but rare metastasisSCC
Chronic draining sinusesSCC
Ulcerative red lesions with scalingSCC
Actinic keratosis is a precursorSCC
KeratoacanthomaSCC variant
- grows rapidly (4-6 weeks) and may regress spontaneously
Significant risk of metastasisMelanoma
S-100 tumor markerMelanoma
Fair-skinned persons are at ↑ riskMelanoma
Depth of tumor correlates with risk of metastasisMelanoma
ABCDEs of melanomaAsymmetry
Border irregularity
Color variation
Diameter > 6mm
Evolution over time
Activating mutation in BRAF kinaseMelanoma
vemurafenibMelanoma in pts with BRAF V600E mutation
Which growth pattern increases the risk of melanoma metastasis?Active vertical growth (Down into the deep dermis)
Blue lesion under the nail, tender to touchGlomangioma (SM cell tumor)