Skin Flashcards by Jung Yum

Sx of bullous pemphigoid

Blisters of the skin most commonly in extremities (Negative Nikolsky sign); oral mucosa is spared (vs. Pemphigus vulgaris)

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Etiology of bacterial skin abscess

Almost always staph

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___lesions are characterized by central, ulcerated crater surrounded by telangiectatic (dilated) vessels

Basal cell carcnioima (“pink-pearl-like”)

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Superficial skin infection not associated w/ systemic sx

Impetigo

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Histology of pemphigus vulgaris

1) Acantholysis of stratum spinosum keratinocytes
2) “Tombstone” appearance- due to basal layer cells that remain attached to BM via hemidesmosomes

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Mutation that drives dysplastic nevi/ melanonva

BRAF kinase, which results in loss of CDK inhibitor

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Another type of lesion (besides skin) found in pemphigus vulgaris

Oral mucosal bullae (blisters)

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Present as pigmented raised lesion w/ central darker shade

Dysplastic nevi

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Melasma and risk factors

Hyperpigmentation of cheeks (can be elsewhere); risk factors include pregnancy (“mask of pregnancy”) and OCP use

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Presented as pigmented raised lesion w/ central darker shade

Dysplastic nevus

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_________: condition characterized by auto IgG antibodys against hemidesmosome components, particularly _________

Bullous pemphigoid; BP180

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Histology of psoriasis (3)

1) Acanthosis w/ elongation of rete ridges + dermal papillae
2) Parakeratosis
3) Munro microabscesses

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Signs + sx of SJS/TEN

Fever, bullae/ skin necrosis, sloughing of skin, involvement of mucous membrane (lip/ oral mucosa)

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__________is the most important prognostic factor in predicting metastasis of melanoma, not the size

Breslow thickness

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Two growth phases of melanoma and main difference

1) Radial growth- melanocytes grow horizontally along DE junction; lack metastasizing ability
2) Vertical growth- melanocytes grow vertically into dermis- tumor gains metastatic potential

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Premalignant lesoin to squamous cell carcinoma

Actinic keratoses; many lesions show dysplastic changes; risk of SCC proportional to degree of epithelail dysplasia

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Condition in which there is IgA deposition at the tips of dermal papillae

Dermatitis herpetiformis

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Presentation of actinic keratosis

Small, rough + scaly (“sand-paper like”), red or brownish papules or plaques

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Disease associated w/ dermatitis herpetiformis

Celiac

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Risk factor of development of basal cell carcinoma

UVB induced damage- sunlight, albinims, xeroderma pigmentosum

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Diseases associated w/ positive Nikolsky sign

1) Pemphigus vulgaris
2) Scalded skin syndrome

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Infection associated w/ Lichens Planus

Chronic hep C

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How is scalded skin syndrome + TEN/SJS distinguished from each other?

Level of skin separation using histology- separation in SJS/TEN occurs between dermal-epidermal junction (Hemidesmosomes), while scalded skin syndrome involves stratum granulosum w/ spinosum

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Presentation of melanoma

Mole-like growth w/ ABCDE

Asymmetry, borders irregular, color not uniform, diameter > 6 cm, evolution over time

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What embryological tissue derives melanocytes

Neural crest

Bacterial infection that involves epidermis, deeper dermis, subcutaneous fat

Cellulitis

Presentation of intradermal nevi vs. junctional nevi

Intradermal nevi- papules Junctional nevi- flat macules

Causes of impetigo

S aureus, S pyogenes

Rosacea

Inflammatory skin disorder characterized by eryhtematous papules + pustuels but no comedones; occurs in ages 30-50 (vs. acne vulgaris)

Well-defined, slightly raised eryhthematous, shiny lesion

Erysipelas

Xeroderma pigmentosum

Autosomal recessive defect in enzymes necessary for nucleotide excision repair (sunlight can induce formation of pyrimidine dimers, which are normally excised by DNA repair). Increased risk for all 3 types of skin CA

Location of melanin synthesis and precursor molecule involved

Melanocytes synthesize melanin in melanosomes, using tyrosine (tyrisinase) as precursor molecule.

6 Ps of Lichens Planus

Pruritic, planar, polygona, purple papules + plaques

Histology of SJS/TEN

Complete separation of epidermis from dermis

Type of moles that are associated w/ increased for melanoma `

Congenital melanocytic nevi, esp. giant congenital nevi (\> 20 cm diameter)

Histology of seborrheic keratosis

horn cysts (kertain filled cysts) + hyperkeratosis

What kind of epithelial junction connects keratinocytes in stratum spinosum?

Desmosomes

Why there is antibody deposition at the dermal papillae in dermatitis herpetiformis

IgA against gluten cross-react w/ reticulin in basement membrane of dermal papillae

characterized by well circumscribed, salmon-colored plauqes w/ loosely adherent silvery scale

Psoriasis

Superficial skin infection involving epidermis + upper dermis

Erysipelas

Warning signs of necrotizing fasciitis (2)

1) Pain out of proportion to acute physical findings 2) Local eryhtema + swelling w/ tenderness beyond confines of infection

Eczema

Definition: pruritic, erythematous, oozing rash w/ vesicles + edema

benign neoplasms of melanocytes

Moles (nevus)

Classic location of squamous cell carcinoma lesions

Lower lip

Pathophysiology of SJS/TEN

Drug somehow activates cytotoxic T cells to kill keratinocytes

Histology of Lichens planus

Inflammatory infiltrate of dermal-epidermal junction w/ "saw tooth" appearance

Type of hypersensitivity involved in atopic dermatitis (eczema)

Type I hypersensitivity to enviornmental antigens

Cause of actinic keratosis

Sun exposure; usually in light pigmented individuals

Dysplastic nevus syndrome- AD disorder associated w/ LOF of \_; pts are at increased risk for melanoma

CDK inhibitor, leading to cell cycle dysregulation

Cause of cellulitis

S. pyogenes, S aureus (less common)

Etiology of erythema multiforme

Assoicated w/ HSV infection (+ mycoplasma), drugs (e.g. PCN, sulfonamide), autoimmune diseases, malignancy

Allele associated w/ psoriasis

HLA-Cw

Immunofluorescence of _ shows IgGs surrounding keratinocytes in a "fish net pattern"

Pemphigous vulgaris

\_ are characterized by small, rough + scaly (sand-paper like), erythematous/brownish papules or plaques

Actinic keratosis

Histology of basal cell carcinoma

Nodules of basal cells w/ peripheral palisading

Inflammation of venules in subcutaneous fat results in inflammation of fat --\> pain, red nodular areas

Erythema nodosum

Other risk factors of squamous cell carcinoma besides UVB-induced damage

Immunosuppressive therapy, arsenic exposure, chronic inflammation (e.g. non-healing wounds, scar from burns, draining sinus tract)

What is the stem cell layer of skin?

Stratum basalis

Lesler Trelat sign and what it suggests

Sudden onset of multiple seborrheic keratosis; suggests underlying carcinoma (esp. GI, lymphoid)

Conditions associated w/ acanthosis nigricans (2)

1) Insulin resistance (e.g. non insulin dependent DM) ## Footnote 2) GI malignancy especially gastric carcinoma

characterized by formation of keratin pearls

Squamous cell carcinoma

Characterized by increased number of melanosomes (melanocytes are not increased), resulting in increased number of melanin production

Freckles (Ephelides)

Which organism is involved in acnes vulgaris and how?

Propionibacterium acnes within hair follicles produces lipases, which break down sebum, which results in release of proinflammatory fatty acids and inflammation of follicle --\> pustule (pimple)

Blisters of pemphigus vulgaris vs. bullous pemphigoid

Pemphigus vulgaris bullous rupture easily (positive Nikolsky sign) while bullous of bullous pemphigoid do not

Histology of dysplastic nevi

Irregular melanocytes that form clusters at the DE junction

"Coin-like, waxy, velvety, stuck on" lesion

Seborrheic keratosis

which layer of skin has connective tissue, nerve endings, blood + lymphatic vessels, and adnexal structures?

Dermis

Component and layer that exfoliative toxin A + B of S aureus targets in scalded skin syndrome

Desmogleins (desmosomes) of stratum granulosum

LOCALIZED loss of skin pigmentation due to autoimmune destruction of melanocytes

Vitiligo

Type of hypersensitivity associated w/ urticaria

Type I hypersesntivity to allergens (re-exposure to allergen results in mast cell dgranulation)

Tumor marker associated w/ melanoma

S-100

Cause of albinism

Defect anywhere along pathway from melanin syntehsis to take-up by keratinocytes; most often due to tyrosinase defect (impairs melanin production)

Munro abscesses and condition associated

Collections of neutrophils in stratum corneum; seen in psoriasis

Sx of dermatitis herpteformis

Prurutic vesicles + bullae that are grouped

White lines on surface of the lesions of Lichens Planus

Wickham striae

Skin finding of squamous cell carcinoma

ulcerated, nodular mass usually on face (classicall on lower lip)

Classic location of basal cell carcinoma lesion

Upper lip

Characteristics of benign moles

Reverse of ABCDE (Asymmetry, Border irregularity, Color variation, Diameter \> 6mm, Evolution over time)

Targetoid rash + bullae

Erythema multiforme

\_ is characterized by NORMAL melanocyte NUMBER w/ DECREASED melanin PRODUCTION

Albinism

Immunofluorescence of dermatitis herpetiformis

Granular IgA deposition at tips of dermal papillae

Immunofluorescence of Bullous Pemphigoid

IgG antibodeies between dermis + epidermis