4th Exam: Skin Diseases Flashcards Preview

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Flashcards in 4th Exam: Skin Diseases Deck (62)
1

Macule:

Flat, often circumscribed color difference, often red, brown, ex: measles

2

Papule:

Elevated, dome shaped, diameter < .5cm, ex: Lichen planus

3

Plaque:

Elevated lesions, flat top, larger than papules, diameter > .5cm, ex: eczema

4

Vesicle:

Blisters, water-filled, diameter <0.5 cm, ex: Herpes simplex

5

Bulla:

Larger blister than vesicles, diameter > 0.5cm, ex: bullous pemphigoid

6

Pustule:

Raised, yellow or white, polys in vesicles, ex: Herpes simplex

7

Crusting:

Vesicles or pustules break, contents dry and harden, ex: Herpes simplex

8

SCale:

White lesions, thickened Stratum Corneum, hyperkeratosis, ex: psoriasis, ichthyosis

9

Hyperkeratosis:

Thickened Stratus Corneus of keratin layer (causes SCales), ex: psoriasis, ichthyosis, actinic keratosis

10

Parakeratosis:

Nucleated cells in stratum corneum (normally no nuclei, keratin, dead cells), rapid proliferation of epi, ex: psoriasis

11

Papillomatosis:

Epidermis forms papillae, hyperplastic, ex: wart

12

Acanthosis:

Thickened epidermis, uniform or irregular, ex: lichen planus

13

Spongiosis:

Intercellular edema, vacuoles bw epi cells, cause: acute injury, ex: eczema

14

Acantholysis

Loss of cohesion bw keratinocytes, spaces bw cells, ex: Pemphigus

15

Eczema:

Nonspecific clinical term, prototype for many rashes, acute/ subacute/ chronic, red, vesicular, oozing, crusting, later: raised scaling plaques, pruritis (itchy)

16

Causes of Eczematous Rashes:

Contact dermatitis, atopic dermatitis/ allergy, seborrheic dermatitis, red, vesicular rash, spongiosis gives way to vesicles

17

Contact dermatitis causes:

Detergent, nickel, poison ivy

18

Rash not where the allergy is:

Atopic dermatitis/ allergy

19

Atopic dermatitis/ allergy:

Often kids, cause unknown, genetic in some cases, stimulus: food or clothing?, Pt often has asthma, allergic rhinitis, often chronic w acute episodes

20

Seborrheic dermatitis:

Stasis dermatitis (sluggish leg veins), drug reaction, type of eczematous rash, common, 5-10% of healthy, 1/3rd of AIDS pts, chronic, waxing and waning, hairy regions, esp face, eyebrows, scalp, around sebaceous glands, bilateral, symmetrical, itching variable, lipophilic yeast, Pityrosporum ovale, mildest form: dandruff; fine white scale, may have erythema, patches/plaques

21

Tx for Seborrheic dermatitis:

Anti-fungal, shampoo 2-3 X wk, zinc pyrithione (Head and Shoulders), selenium sulfide, ketoconazole

22

Inflammatory Scaling Papule & Plaques:

Dermatophytes, psoriasis, pityriasis rosea, 2’ syphilis, lichen planus

23

Pityriasis rosea:

“bran-like scale", young adults, seasonal, usually winter, often URI before, cellular Type IV immune response, antigen unknown, acute, self-limited, mostly trunk, neck

24

Pityriasis rosea rash:

Herald patch (initial rapidly enlarging oval-shaped red papulosquamous lesion, usually trunk, heralding widespread eruption of pityriasis rosea in 7-14d), first, often largest, many lesions after several days, round to oval, tan/salmon color, look like bran/ corn flakes, itching is common, delicate scaling, elevated patches

25

Ddx of Pityriasis rosea:

Psoriasis, lichen planus, tinea corporis (ringworm), 2’ syphilis

26

Tx for Pityriasis rosea:

Usually spontaneous remission in 2-4wks, recurrence rare

27

Lichen planus:

Cause unknown, probably immune-mediated, more common in women, Ig deposits at dermal-epidermal jx, some cases assoc w Hep C, involves skin & mucous membranes, oral lesions, 70% pts, esp. wrist and ankle, oral manifestation: red gum tissue, multiple lesions, purple, planar (flat) or papular, polygonal, pruritic (itchy), self-limited, resolves in mos-2yr, multiple papules w Wickham striae (whitish lines visible in papules of lichen planus and other dermatoses, typically the macroscopic appearance of the histologic phenomenon hypergranulosis), white dots = thickened granular layer

28

Histology of Lichen planus:

Hyperkeratosis, thickened granular layer (almost diagnostic), irregular acanthosis (saw tooth D-E jx), band-like lymphocytic infiltrate (degeneration of basal layer)

29

Vesicles of Lichen planus are often:

exanthems

30

exanthems:

widespread rash usually occurring in children

31

Possible causes of exanthems:

Varicella, herpes simplex, herpes zoster, enterovirus

32

bullous/vesicular skin diseases (large, fluid filled)
hard or flaccid:

Pemphigus vulgaris, bullous pemphigoid, dermatitis herpetiformis (DH), porphyria, contact dermatitis, drug reaction/eruption, impetigo, scalded skin syndrome

33

Pemphigus vulgaris:

Middle aged+, generalized bullae, anywhere on skin surface, oral lesions common, bullae flaccid, 1-10 cm, rupture easily → bleeding erosions → skin infection, mortality 8-10%, INTRAepidermal, suprabasilar bullae, only disease to have suprabasilar → DIAGNOSTIC, Begins w acantholysis, intercellular IgG, C3, autoantibodies to desmoglein 3 (adhesion molecule), Ab titer predicts course

34

Tx for Pemphigus vulgaris:

Steroids

35

only disease to have suprabasilar, DIAGNOSTIC:

Pemphigus vulgaris

36

acantholysis:

loss of intercellular connections such as desmosomes resulting in loss of cohesion bw keratinocytes, not seen in bullous pemphigoid

37

Autoantibodies to desmoglein 3:

located in desmosomes, Anti-desmoglein 3 Ab → Intercellular fluorescent deposits

38

Bullous pemphigoid:

50-70yo, bullae in flexor areas (groin, axilla), ral lesions: 1/3 pts, very pruritic, tense bullae, 1-5 cm, heals wo scar, most subside in mo-1yr, subepidermal bullae, linear IgG, C3 at BM (lamina lucida), autoantibodies to hemidesmosome proteins, BP 180 and BP 230, intracellular and lamina lucida location, Ab binding to Ag seen in skin BM (LL – lamina lucida, LD - lamina densa), immunofluorescent deposits at BM (Only at the DE junction), like lichen planus, DM, SLE

39

Rx for Bullous pemphigoid:

steroid, like pemphigus vulgaris

40

Porphyria cutaea tarda:

Abnormal porphyrin metabolism (urodecarboxylase missing in cutaneous porphyria), most common porphyria, familial, autosomal dominant, uroporphyrinogen decarboxylase deficiency → build up of porphyrins, Dark brown urine; ↑ uroporphyrin, lesions precipitated by alcohol, sunlight, photosensitive skin lesions, esp hands (dorsum)

41

Photosensitive skin lesions, esp hands (dorsum)

Subepi bullae, excess hair, esp forehead, temples, cheeks, neck

42

Recap of pemphigoid:

tense bullae, subepidermal, Ig at BM, hemidesmosomes

43

Recap of pemphigus:

flaccid ullae, suprabasillar, Ig are intracellular, desmoglein 3

44

Recap of porphyria CT:

Tense bulla, subepidermal, Ig at De jx, absent UPDC

45

These both have tense bullae and are subepidermal:

pemphigoid, porphyria

46

Generalized erythema:

Drug eruption, Viral, Toxic, SLE, DM

47

Viral, generalized erythema may be due to:

Rubella, measles, Roseola (HHV6), erythema infectiosum (parvo B19)

48

Toxic, generalized erythema may be due to:

Scarlet fever-GAS, fever, pharyngitis (erythrogenic exotoxin, rash on face (circumoral pallor), arms, legs, trunk), scalded skin-Staph toxin, infants, fever, toxic shock syndrome-Staph and GAS

49

Localized lesions w erythema:

Cellulitis, erysipelas-GAS, face, well-demarcated, fever, acute, swelling (type of cellulitis), rapid progression, impetigo- Staph/GAS, preschool children, face & neck, erythema nodosum, erythema multiforme, erythema migrans-Lyme disease

50

Erythema nodosum:

Assoc w infections/immune mediated disease, type of panniculitis (subcutaneous), acute presentation (fever, malaise), often self-limited, but may be recurrent, rash: often lower legs (multiple, deep, tender nodules)

51

infections/immune mediated disease assoc w erythema nodosum:

TB, sarcoidosis, IBD, beta strep infections

52

panniculitis:

subcutaneous, below the skin- looks like a skin disease, but isn’t

53

Tx for Erythema nodosum:

aimed at underlyling disease

54

Early histo findings of Erythema nodosum:

polys, fibrin, deposits of Ig and C

55

Semi-progressed histo findings of Erythema nodosum:

granulomatous inflammation, looks like TB

56

Late histo findings of bands of Erythema nodosum:

bands of fibrosis

57

Erythema nodosum is marked by chronic inflammation w this cell type:

giant cell

58

Erythema mulitforme causes:

o Drugs
• Sulfonamides, penicillins, salicylates
o Infection, esp herpes simplex
o Cancer
o Collagen disease
o Idiopathic

59

Pathogenesis of Erythema mulitforme:

• Epidermal cells killed by T cells
• Cytotoxic CD8+ lymphocytes located at D-E jx

60

population most affected by Erythema mulitforme:

older children, young adults

61

Lesions of Erythema mulitforme:

Symmetrical, often extremities, classically look like a target (erythematous rim and center- diagnostic/signature lesion (esp if on extremities) )

62

Histology of Erythema mulitforme:

Red, round, circumscribed, target-like, multiple, lymphocytes at D-E jx (migrate into epidermis, attack keratinocytes)