Skin Flashcards
Epidermis layers: superficial to deep
corneum
Granulosum
spinosum
basalis
Stem cell layer of epidermis
Basalis
Layer with desmosomes
Spinosum
Granules in keratinocytes
Granulosum
Keratin in anucleate cells
Corneum
Structures found in dermis
CT, nerve endings, blood and lymphatic vessels, adnexal structures (hair shafts, sweat glands, sebaceous glands)
Atopic Dermatitis
Eczema
Pruritic, erythematous, oozing rash with vesicles and edema
Face/flexor surfaces
Type 1 hypersensitivity
Atopic Dermatitis associated with
Asthma and allergic rhinitis
Contact dermatitis
Pruritis, erythematous, oozing rash with vesicles and edema
Allergen exposure: Poison ivy/nickel jewelry (T4H), Irritant chemicals, Drugs
TX: remove allergen & topical glucocorticoids
Acne Vulgaris
Comedones (white & blackheads)
Pustules (pimples)
Nodules (scars)
Chronic inflammation of hair follicles and sebaceous glands
P acnes - lipases break down sebum - result in proinflammatory FA
TX: benzoyl peroxide & VIT A Derivatives
Psoriasis
Salmon-colored plaques w/ silvery scale
Extensor surfaces & scalp
PItting of nails
Excessive keratinocyte proliferation
AI: HLA-C
In areas of trauma
Psoriasis HLA association
HLA-C
Histology of psoriasis
- Acanthosis (epidermal hyperplasia)
- Parakeratosis (hyperkeratosis w/ retention of keratinocyte nuclei in corneum - results in silvery scale)
- Neutrophils in corneum (Muncro microabscesses)
- Thinning of epidermis above elongated dermal papillae (Auspitz sign)
TX psoriasis
Corticosteroids, PUVA, immune-modulating therapy
Lichen Planus
4 P’s
Pruritic, planar, polygonal, purple papules
Wrists, elbows, mucosa (Wickham striae - reticular white lines on surface)
Saw tooth appearance of inflammation at dermal/epidermal junction
Associated w/ chronic Hep C
Pemphigus vulgaris
AI destruction of desmosomes in spinosum
IgG against desmoglein (T1H0
Skin and oral bullae
Acanthyolysis of spinosum - suprabasal blisters
Thin walled/rupture easily (Nikolsky sign)
IF: IgG surrounding keratinocytes: Fish net pattern
Bullous pemphigus
AI of hemidesmosomes between basal cells and BM
IgG against hemidesmosomes (BP180) of BM
Skin blisters - mucosa spared
Basal cell detaches from BM - tense bullae hard to rupture
IF: linear pattern - IgG along BM
Dermatitis Herpetiformis
IgA deposition at tips of dermal papillae
Pruritic pustules/bullae
Associated with celiac dz - Ab against gluten
Erythema Multiforme
Hypersensitivity Rxn
Targetoid rash and bullae - targetoid d/t necrosis at center
HSV most common
Other: Mycoplasm infection, drugs, AI, malignancy
Erythema Multiforme with oral mucosa/lip involvement and fever:
SJS
TEN (toxic epidermal necrolysis is severe form SJS) - diffuse sloughing of skin - adverse drug rxn
Seborrheiic keratosis
Benign squamous proliferation
Sudden onset of multiple seborrheic keratosis related to (and name of sign)
Sign: Leser Trelat
Suggests underlying GI carcinoma
Acanthosis nigricans
Insulin resistance or gastric carcinoma
Basal cell carcinoma
Most common form of cutaneous malignancy
UVB (also albinism/xeroderma pigmentosum)
Histology shows peripheral palasading nodules of basal cells
TX: excision
Classic location BCC vs SCC
BCC: upper lip
SCC: lower lip
SCC
Keratin pearls
UVB (also albinism/xeroderma pigmentosum)
Additional factors: Immunosuppressive therapy, arsenic exposure, chronic inflammation
TX: excision
SCC precursor
Actinic keratosis - hyperkeratotic, scaly plaque, face, neck, back
Keratoacanthoma
Develops rapidly/regresses spontaneously
Cup shaped tumor w/ keratin debbis
What are melanocytes derived from?
neural crest
Melanin synthesis
Tyrosine to melanin then pass malanosomes to keratinocytes
Freckle d/t
increased number of melanosomes
Nevus
Benign neoplasm of melancytes
Children: dermal-epidermal junction (junctional nevus)
Adults - lose junctional component - results in intradermal nevus
Variants of Melanoma
- Superficial spreading - most common: early radial growth
- Lentigo maligna melanoma - lentiginous proliferation (radial growth)
- Nodular: early vertical growth (poor prognosis)
- Acral lentiginous - palms/soles of dark skin people - no related to UV
Impetigo
Superficial infection S aureus/S pyogenes Erythematous macule - progress to pustules Face Erosion & dry - honey crusted
Cellulitis
deeper (dermal/subcutaneous) infection
S aureus/S pyogenes
Surgery, trauma, bug bite
What can cellulitis progress to
Necrotizing fasciitis
Necrosis of subcutaneous tissue d/t infection w/ anaerobic “flesh eating” bacteria
Co2 production = crepitus
Surgical emergency
Staph Scalded Skin syndrome
Sloughing of skin w/ erythematous rash
Skin loss
Exfoliative toxin A & B - epidermolysis of stratum granulosum
SSSS vs TEn
SSSS: stratum granulosum
TEN: between dermis and epidermis
Molluscum contagiosum virus
poxvirus
keratinocytes show cytoplasmic inclusions
