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
Private	No

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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