Inflammatory Skin Disease (complete) Flashcards

1
Q

What are common causes of irritant and allergic contact dermatitis?

A

1) Atopic Dermatitis

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2
Q

What is atopic dermatitis?

A
  • Common skin disease

- Can begin at any age (majority <5yo)

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3
Q

What are the diagnostic criteria for atopic dermatitis?

A

MUST HAVE: itchy skin and three or more of the following:

  • H/o of skin crease involvement
  • H/o asthma or hay fever
  • H/o dry skin in last year
  • Visible flexural eczema
  • Onset under 2 years
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4
Q

What is the pathogenesis of atopic dermatitis?

A
  • Barrier disrupted skin
  • Filaggrin mutation
  • S. aureus acts as superAg
  • Elevated IgE
  • Eosinophilia
  • Th2 cytokine production (IL4,5,&10)
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5
Q

Describe infantile atopic dermatitis

A

Birth - 2 yo

  • Dry, red scaly areas — confined to cheeks
  • Becomes flushed w/ exposure to cold
  • Some will have a generalized eruption (erythematous papules, redness, scaling, areas of lichenification)
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6
Q

Describe childhood atopic dermatitis

A

Involvement of flexural skin

  • antecubital fossa
  • popliteal fossa
  • neck
  • wrists
  • ankles
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7
Q

Describe adult atopic dermatitis

A
  • occurs on eyelid and/or hand

Characterized by:

  • dry skin
  • keratosis pilaris
  • ichthyosis vulgaris
  • hyperlinearity of palms
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8
Q

Describe irritant contact dermatitis

A
  • non-immunological mediated rxn => direct cytotoxic effect
  • Can be from a single/repeated exposure
  • MOST COMMON type of contact dermatitis

No specific test for irritant contact dermatitis

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9
Q

What are the effects of strong irritants associated w/ irritant contact dermatitis?

A
  • Damage skin directly (even w/ small amounts for short time)
  • These agents carry warning labels => suggest wearing gloves

Weak irritants are harmless by themselves but frequent contact may damage skin

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10
Q

What are some examples of weak irritants?

A
  • Soap/water
  • Skin products
  • Perfumes
  • Wool
  • Raw foods
  • Body secretion
  • Friction
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11
Q

Describe allergic contact dermatitis

A
  • Requires exposure of allergen => immune response & development of memory T cells
  • Type 4 delayed-type hypersensitivity rxn => starts 24-48hrs after exposure

Think poison ivy

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12
Q

Describe allergic contact dermatitis on a micro level

A
  • Allergens small chemicals => <500 daltons
  • Smallness allows penetration through skin
  • Langerhans cells present allergen to T cells
  • Require repeat exposure
  • Caused by inflammatory cytokines including TNF-alpha and IL-1
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13
Q

What do you patch test?

A
  • Used for diagnosing allergic contact dermatitis
  • pts have suggestive history
  • pts w/ resistant dermatitis
  • chronic dermatitis
  • occupationally related dermatitis
  • Atopic eczema
  • stasis dermatitis
  • photo/airborne distribution
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14
Q

What are some contact allergens?

A
  • Nickel
  • Balsma of Peru
  • Neomycin
  • Fragrances
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15
Q

What are some risk factors associated with nickel sensitivity?

A
  • Being female
  • Younger age
  • Ear piercing
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16
Q

Describe fragrance allergies

A
  • > 2800 fragrance ingredients
  • > 100 are known contact allergens
  • Unscented products may have a masking fragrance — need to use fragrance-free products
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17
Q

Describe bacitracin and neomycin allergies

A
  • Can occur together

- Co-sensitization: allergy to two allergens not structurally related but often used together

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18
Q

What are drug eruptions?

A

Delayed-typer hypersensitivity rxns

  • Most common type
  • Usually Type 4 hypersensitivity

Usually begins 7-14 days after starting new med

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19
Q

Describe exanthematous eruptions

A
  • 10-20% in children are drug-induced
  • 50-70% in adults are drug-induced

Tx: stop cause (infection), supportive w/ topical steroids, anti-histamines

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20
Q

What are some responsible drugs associated with exanthematous eruptions?

A
  • AminoPCNs
  • Sulfonamides
  • Cephalosporins
  • Anticonvulsants
  • Allopurinol
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21
Q

Describe stasis dermatitis

A
  • Associated w/ other signs of venous insufficiency
  • ONLY in lower extrememties

Think:

  • Varicose veins
  • Chronic lower extremity edema
  • Venous stasis ulcers
  • Lipodermatosclerosis
22
Q

What are complicating factors associated with stasis dermatitis?

A
  • dryness
  • itching
  • allergic contact dermatitis
  • irritant dermatitis due to wound exudates
23
Q

What is the treatment for stasis dermatitis

A
  • Compression
  • Elevation
  • Exercise calf muscles
  • Vascular surgery
  • Topical steroids
  • Avoid allergens
24
Q

What is lichen simplex chronicus?

A
  • thick, scaly plaques
  • Cause: chronic rubbing, scratching
  • Tx: topical steroids first, then antihistamines

Pts need to be counseled to break cycle

25
Q

Describe venous stasis ulcers

A
  • Common in pts w/ h/o leg edema, varicose veins, blood clots
  • Found in medial lower leg
  • Red w/ yellow fibrinous base
  • Borders irregularly shaped
  • May be purulent
26
Q

Describe nummular dermatitis

A

AKA: discoid eczema

  • Often in legs, but also arms, trunk
  • Most common in men >50yo
  • round patches: red, scaly, crusty
  • Tx: moisturization, minimize soap, topical steroids
27
Q

What is the morphology of dermatitis?

A
  • Erythematous papules

- Thin plaques w/ scale

28
Q

What is the morphology of erysipelas?

A

Warm, tender, erythematous, sharply demarcated, raised plaque

29
Q

What is the morphology of cellulitis?

A

Warm, tender, erythematous patches OR plaques

30
Q

Where is the inflammation in dermatitis?

A
  • Epidermis

- Dermis

31
Q

Where is the inflammation in erysipelas?

A
  • Dermis

- minimal SubQ tissue

32
Q

Where is the inflammation in cellulitis?

A
  • Dermis

- SubQ tissue

33
Q

Describe seborrheic dermatitis

A
  • Facial involvement
  • Symmetric over medial eyebrows, nasolabial folds, ears
  • Occurs in areas w/ sebaceous glands (scalp, face, ears, chest)
  • ALSO dandruff
34
Q

Describe the pathogenesis of seborrheic dermatitis

A
  • Maybe b/c of a combo of overproduction of skin oil and yeast irritation (malassezia furfur)
  • Increased disease linked to Parkinsons, head injury, stroke, HIV
35
Q

Describe psoriasis

A
  • Affects 2% of pop’n
  • Positive FH in 36% of psoriasis
  • Impacts QOL

Clinical:

  • Chronic plaque disease
  • Guttate
  • Erythroderma
  • Pustular psoriasis
  • Arthritis
36
Q

What are co-morbidities associated w/ psoriasis?

A
  • Independent risk factor for CV disease

- Pts in 40s: double risk for MI, RR increases by 20%

37
Q

Describe the treatment in localized psoriasis

A
  • Calcipotriol
  • Corticosteroids
  • Topical retinoids
  • Phototherapy
38
Q

Describe the treatment in widespread psoriasis w/ or w/o arthritis

A
  • Methotrexate
  • Cyclosporin
  • Systemic retinoids
39
Q

CHEAT SHEET

Where does stasis derm present?

A

Lower legs

40
Q

CHEAT SHEET

Where does seborrheic derm present?

A

Scalp

41
Q

CHEAT SHEET

Where does atopic derm present?

A

Flexor surfaces

42
Q

CHEAT SHEET

Where does psoriasis present?

A

Extensor surfaces

May include arthritis

43
Q

CHEAT SHEET

What is the cause of stasis derm?

A

Lower extremity edema

44
Q

CHEAT SHEET

What is the cause of seborrheic derm?

A

Malassezia furfur

45
Q

CHEAT SHEET

What is the cause of atopic derm?

A

Filaggrin

46
Q

CHEAT SHEET

What is the cause of irritant derm?

A

Common irritants

47
Q

CHEAT SHEET

What is the cause of allergic contact derm?

A

Common allergens

48
Q

CHEAT SHEET

What is atopic dermatitis associated with?

A

Asthma

Allergic rhinitis

49
Q

CHEAT SHEET

What type of hypersensitivity is associated with allergic contact dermatitis?

A

Type 4 (delayed type hypersens rxn)

50
Q

CHEAT SHEET

How is allergic contact dermatitis tested for?

A

Patch testing

51
Q

CHEAT SHEET

What is psoriasis associated with?

A

Increased risk for CV disease