Dermatoses - Class material
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- A verrucous skin-colored plaque
- Wart (verrucous vulgaris)
- Etiology of warts
- HPV
- Histology of warts
- vacuolated cells, hyperkeratosis
- Erythematous plaque with white mica-like scaling
- Psoriasis
- Pathogenesis of psoriasis
- Immunological disease (T cell activation) leading to hyperproliferation of epidermis
- What is the Auspitz sign and in what derm lesion do you see it?
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scraping of lesion/scales causes punctate bleeding due to thin epidermis
psoriasis - Describe histology of psoriasis
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↑ stratum corneum
↓ stratum granulosum - What is the Koebner effect?
- Physical trauma in psoriatic patient will induce psoriasis
- Hypopigmented macules and patches
- Tinea versicolor
- Etiology of tinea versicolor?
- Malassezia furfur
- How dx tinea versicolor?
- KOH scraping of stratum corneum → spaghetti and meatballs (hypae and spores)
- Tan-colored macules and patches
- Tinea versicolor (lesions turn brown under sun)
- Erythematous patch of nasal-labial folds
- Seborrheic Dermatitis
- What areas does seborrheic dermatitis have a predilection for?
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Areas with sebaceous glands:
scalp
forehead
eyebrows
nasal folds - Erythematous pustules, papules, and nodules
- Acne
- Name 3 causes of acne
-
(1) propionobacterium (contains lipase which TCA → FA)
(2) hormonal (↑ sebaceous gland activity)
(3) epidermal (hyperkeratinization) - Verrucous medium-brown plaque
- Seborrheic keratoses
- What derm lesion do you see pseudohorn cysts of keratin?
- Seborrheic keratoses
- What is the prognosis of seborrheic keratoses?
- benign, don't need to treat
- Erythematous edematous, skin-colored papules
- urticaria
- wheel and flare
- urticaria
- Name some common causes of urticaria
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Drugs (penicillin, aspirin)
Food (shellfish)
Physical (cold, heat, light, pressure -- underwear) - Erythematous annular patches with slightly elevated border and scaling
- Tinea dermatophysis (tinea corporis -- ringworm)
- How dx tinea dermatophysis?
-
KOH prep --> only hyphae
Wood light (tinea fluoresces)
culture with sabarose medium -
Many oval erythematous patches
Long axis along lines of cleavage (Christmas tree sign)
Mother patch - Pityriasis Rosea
- If pityriasis rosea suspected, what test should you do?
- VDRL for secondary syphilis (mimics PR)
- Small erythematous macule with honey-colored crust (filled with neutrophils)
- Impetigo
- What causes impetigo?
- Staph or Group A Strep
- Pearly border with central telangiectasis
- Basal cell carcinoma
- Translucent papule with telangiectasias and central ulcer (name general skin lesion and subtype)
- Basal cell carcinoma -- nodular ulcerative
- Name 4 types of basal cell carcinoma
-
Nodular-ulcerative
Pigmented
Superficial
Sclerosing - Grouped vesicles on erythematous base
- HSV
- What test do you use to confirm HSV?
- Tzanck smear (multinucleated giant cells) and Cowdry A inclusions (intranuclear inclusions)
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Erythematous patches with scaling
Intracellular edema
Microvesiculation
Sharp lines of demarcation - Contact dermatitis
- Light tan-colored papule with regular appearance (sometimes with hair)
- melanocytic nevus
- Straight pigmented line on nail bed
- Melanocytic nevus
- Risk of what with melanocytic nevus?
- Malignant melanoma
- How rule out malignant melanoma if you see a pigmented lesion?
-
Sudden changes (red = inflamm, white = regression, blue = melanin)
Increase in size
Irregular border
Irregular topography
Ulceration, bleeding, itching - Lesion with irregular border, topography, and color
- Malignant melanoma
- What is most important in determining prognosis of a malignant melanoma?
- Depth of invasion (use Breslow method)
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Where are melanomas most found in:
-- men
-- women -
Men: trunk
Women: legs
(sun exposed areas) - Jet black lesion with erythema and white center and irregular borders
- Melanoma with regression
- Hyper- and hypopigmented skin, erythematous, scaling macules
- Actinic Keratoses
- Who's most at risk of actinic keratoses and in what areas?
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Fair-skinned people
Sun-exposed areas - Actinic keratoses predisposes to what neoplasm?
- Squamous cell carcinoma of skin
- Erythematous patches in cubital fossa and other flexor areas, pruritic
- Atopic dermatitis
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Patient has FHx of rhinitis, asthma, hay fever, and hives (sucks, huh?).
What skin disorder is he at risk for? - Atopic dermatitis
- Compare allergic contact dermatitis and atopic dermatitis
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Allergic contact: need specific antigen
Atopic: Th-2 driven response, diathesis, triad of rhinitis, hay fever, dermatitis