Y2S1B1 - Path - Pathoma derm Flash Cards

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Title: Y2S1B1 - Path - Pathoma derm
Description: derm chapter
Number of Cards: 34
Save Count: 4
Author: AnnaBamBam
Created: 2012-01-12
Tags: path touro
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    • Question
    • Answer
    • Side 3
    • Type 1 hs reaction on skin, often involving face and flexor surfaces, a/w asthma and allergic rhinitis
    • Atopic dermatitis or eczema
    • Type IV hs reaction on skin, d/t poison ivy, nickey, chemicals (detergents), drugs (penicillin), etc.

      Dx?
      Tx?
    • Contact dermatitis

      tx: remove offending agent and topical glucocorticoids if needed
    • pruritic, erythematous, oozing rash with vesicles and edema
    • could easily be either atopic dermatitis or contact dermatitis! is there an irritant?
    • Hormone-associated increase in sebum production and excess keratin production -> blocks follicles. Bacterial infection produces lipases that break down sebum -> proinflammatory fatty acids -> pustule or nodule

      Dx?
      Tx?
    • Acne vulgaris (bacteria is propionibacterium acnes)

      tx: Benzoyl peroxide (to knock out p. acnes) and in severe cases vitamin A derivatives (isotretinoin) to reduce keratin production
    • Excessive keratinocyte proliferation! Acanthosis, parakeratosis (hyperkeratosis w/ retention of keratinocyte nuclei in stratum corneum), Munro microabscesses neuts in stratum corneum)

      Dx?
      Tx?

      Other more-obvious associated symptoms?

      Why might this be an autoimmune disease?
    • Psoriasis

      tx: corticosteroids, UV w/ psoralen (PUVA), or immune-modulating therapy

      other signs: well-circumscribed, salmon-colored plaques w/ silvery scale, usually on extensor surfaces and scalp; possibly pitting of nails; Auspitz sign

      Autoimmune: a/w HLA-C (genetic susceptibility) and lesion often arises in areas of trauma (environmental trigger)
    • Wickham striae, "saw-tooth" appearance at dermal-epidermal junction, a/w chronic HCV infection, commonly involves wrists, elbows, and oral mucosa

      Dx?
      More description?
    • Lichen Planus

      pruritic, planar, polygonal, purple papules

      wickham striae = reticular white lines on surface of papules or in mouth

      "saw tooth" appearance - inflammation of dermal-epidermal junction

      unknown etiology
    • IgG antibody against desmoglein, type II hs, shallow erosions w/ dried crust on skin and oral mucosa, acantholysis, "tombstone" appearance on histology and "fish net" pattern on IF, +Nikolsky sign

      Dx?
      More info?
    • Pemphigus Vulgaris

      Autoimmune destruction of desmosomes b/w keratinocytes
      suprabasal blisters, basal layer remains attached to BM (tombstone appearance)
      +Nikolsky - thin bullae rupture easily, leads to shallow erosions w/ dried crust
      "fish net" pattern is from IgG surrounding keratinocytes in IF
    • IgG against BM collagen, tense blisters on the skin, IF shows linear IgG along the BM

      Dx?
      Other information?
    • Bullous Pemphigoid

      Autoimmune destruction of HEMIdesmosomes b/w basal cells and BM
      Oral mucosa is spared! unlike pemphigus vulgaris
      also because bullae do not rupture easily, is clinically milder than pemphigus vulgaris
    • Grouped, pruritic vesicles and bullae, with IgA deposition at tips of dermal papillae in a patient with Celiac disease

      Dx?
      Tx?
    • Dermatitis herpetiformis

      tx: gluten-free diet
    • HS reaction, targetoid rash and bullae w/ central epidermal necrosis, in a patient with HSV infection

      Dx?
      Other associations?
    • Erythema Multiforme (EM)

      a/w HSV infection but also a/w Mycoplasma infection, drugs (penicillin and sulfonamides), autoimmune disease (SLE), and malignancy
    • EM with oral mucosa/lip involvement and fever. Dx?
    • Stevens-Johnson Syndrome (SJS)
    • Severe form of SJS characterized by diffuse sloughing of skin, resembling a large burn. Most often due to an adverse drug reaction.
    • Toxic epidermal necrolysis
    • Elderly patient w/ sudden onsent of raised, discolored plaques on extremities and face, coin-like, waxy, "stuck on" appearance. Histology shows keratin pseudocysts.

      What is this? What is it suggestive of?
    • Leser-Trelat sign (sudden onset of multiple seborrheic keratoses, which are benign squamous proliferations and when by themselves are a common tumor in the elderly)

      Suggests underling carcinoma of the GI tract!
    • Epidermal hyperplasia with velvet-like darkening of skin in axilla or groin

      Dx?
      What is this a/w?
    • Acanthosis Nigricans

      a/w insulin resistance (type II DM) or malignancy (especially gastric carcinoma)
    • What are the risk factors for BCC, SCC, and Melanoma?
    • all are UVB-related (except acral lentiginous melanoma) - prolonged exposure to sunlight, albinism, xeroderma pigmentosum

      Additional risk factors for SCC are immunosuppressive therapy, arsenic exposure, and chronic inflammation (ex: scar from burn or draining sinus tract)

      Additional risk factor for Melanoma is dysplastic nevus syndrome (AD disorder)
    • Elevated nodule w/ central, ulcerated crater, telangiectatic vessels
      Histology shows peripheral palisading

      Dx?
      Tx?

      Other info?
    • Basal Cell Carcinoma (BCC)

      tx: surgical excision, metastasis is rare

      "pink, pearl-like papule"

      peripheral palisading means the basal cells in the basal nodule are lining up along the edge
      Classically on UPPER lip
    • Ulcerated, nodular mass on face, histology shows formation of "keratin pearls"

      Dx?
      Tx?

      Classically located where?
    • Squamous Cell Carcinoma (SCC)

      tx: excision, metastasis is uncommon

      Classically on LOWER lip
    • Precursor lesion of SCC, hyperkeratotic, scaly plaque, often on face, back or neck

      Dx?
    • Actinic Keratosis
    • Well-differentiated SCC, develops rapidly and regresses spontaneously; cup-shaped tumor filled w/ keratin debris

      Dx?
    • Keratoacanthoma
    • Melanocytes are derived from what?
    • Neural crest
    • Melanocytes synthesize melanin in melanosomes from what precursor?
    • Tyrosine (requires tyrosinase)
    • Localized loss of skin pigmentation d/t autoimmune destruction of melanocytes. Dx?
    • Vitiligo
    • Congenital lack of pigmentation d/t enzyme defect, usually tyosinase, that impairs melanin production. Ocular or oculocutaneous forms
    • Albinism
    • Increased number of melanosomes, darken when exposed to sunlight
    • Freckle (ephelis)
    • Benign neoplasm of melanocytes, may have hair, flat macule or raised papule
    • Nevus (mole)

      there are congenital and acquired (junctional, compound or intradermal) types

      Dysplasia may arise, which is a precursor to melanoma
    • Most common melanoma with dominant early radial growth phase and good prognosis?
    • Superficial spreading melanoma
    • Melanoma with radial proliferation along the dermal-epidermal junction with good prognosis?
    • Lentigo maligna melanoma
    • Melanoma with early vertical growth and poor prognosis?
    • Nodular melanoma
    • Melanoma on palms or soles in dark-skinned individuals?
    • Acral lentiginous melanoma
    • Erosions with dry, crusted, honey-colored serum on face of a child. Began as erythematous macules that progressed to pustules and ruptured. Dx?
    • Impetigo usually d/t s. aureus or s. pyogenes
    • Red, tender, swollen rash with fever, likely after a recent surgery, trauma or insect bite. Dx?

      If this progresses, it can present with "crepitus" and is a surgical emergency. Why?
    • Cellulitis usually d/t s. aureus or s. pyogenes

      Necrotizing fasciitis w/ necrosis of subQ tissues from anaerobic "flesh-eating" bacteria, "crepitus" is from prodn of CO2
    • Sloughing of skin w/ erythematous rash and fever. What causes this? how is this different from TEN?
    • Staph Scalded Skin Syndrome

      s. aureus exfoliative toxins A and B cause epidermolysis of stratum granulosum, unlike TEN which occurs deeper at the dermal-epidermal junction
    • Flesh-colored papules w/ rough surface usually on hands and feet, shows "koilocytic change"

      Dx?
    • Verruca (wart) d/t HPV infection of keratinocytes
    • Firm, pink, umbilicated papules

      Keratinocytes show cytoplasmic inclusions

      Dx?
      More info?
    • Molluscum Contagiosum

      d/t poxvirus

      cytoplasmic inclusions = "molluscum bodies"

      usually in children; also in sexually active adults and immunocompromised