Dermatology Flashcards
Layers of the epidermis
Corneum
Granulosum
Spinosum
Basalis
Type of hypersensitivity reaction in atopic dermatitis
Type I (asthma, allergic rhinitis)
Type of hypersensitivity reaction in contact dermatitis
Type IV
Pruritus, erythema, oozing, vesciles and edema, on the face and flexor surfaces; hx of asthma
Atopic dermatitis
Dermatitis associated with exposure to allergens
Contact dermatitis
Chronic inflammation of sebaceous glands and hair follicles due to hormone-related excess keratinization of hair shaft and excess sebum production
Acne Vulgaris
Most common etiologic agent of acne vulgaris
C. acnes
Treatment of acne vulgaris
Topical Retinoid/Vit. A - reduces keratin production Topical antibiotics (clindamycin, erythromycin, dapsone), benzoyl peroxide products
Well-circumscribed salmon colored plaques with silvery scale
psoriasis
common areas of psoriatic lesions
extensor surfaces and scalp, in areas of TRAUMA (environmental trigger)
Excessive keratinocyte proliferation of prob. autoimmune etiology
Psoriasis
Auspitz sign
Psoriasis (pinpoint bleed)
Monroe microabscesses
Psoriasis (collection of neutrophils)
Treatment of Psoriasis
Corticosteroids
Immune modulating therapy
UV light (with psoralen) - to damage proliferating keratinocytes
5Ps: pruritic, polygonal, papular, planar, purple
Lichen planus
common areas of lichen planus
wrist, elbows, ORAL MUCOSA
Wickham striae
Lichen planus (reticular white lines)
Inflammation of dermal-epidermal junction
Lichen planus
Sawtooth appearance of dermal-epidermal junction
Lichen planus
skin lesion Associated with chronic Hep C
Lichen planus
Autoimmune destruction of desmosomes (stratum spinosum) due to IgG antibodies agains desmoglein, leading to separation bet. basal cells and other cells of epidermis
Pemphigus vulgaris
Tombstone appearance
Pemphigus vulgaris (basal cells attached via hemidesmosomes)
Fishnet appearance on immunofluorescence
Pemphigus vulgaris - IF highlights IgG
IgG antibody against basement membrane and hemidesmosomes causes subepidermal blisters
Bullous pemphigoid
Differentiate Bullous pemphigois from pemphigus vulgaris
Both are blistering dermatoses - layers of skin are separated however
1) in PV separation is above basement membrane, in BP it separates the BM from the dermis
2) in PV oral mucosa is involved, in BP oral mucosa spared
3) in PV blisters rupture easily, form dried crust, in BP bullae do not rupture easily
Autoimmune IgA deposition on tips of dermal papillae, causing blistering
Dermatitis herpetiformis
Blistering dermatoses Associated with celiac disease; improves w gluten free diet
Dermatitis herpetiformis
Hypersensitivity reaction with targetoid rash and bullae
erythema multiforme
Type of hypersensitivity reaction assoc. with erythema multiforme
Type IV
Erythema Multiforme versus SJS versus TEN
erythema multiforme + oral mucosa involvement + fever = SJS
10% BSA SJS
TEN is severe form usually associated with ADR >30% BSA , + sloughing of skin
Benign squamous proliferation in elderly, “stuck on” appearance
seborrheic keratosis
Contains pseudocysts - circular spaces w pink keratin
seborrheic keratosis
Sudden onset of multiple seborrheic keratoses suggesting underlying GI carcinoma
Leser- Trelat sign
Epidermal hyperplasia with darkening of skin, velvet-like
acanthosis nigricans
common areas of acanthosis nigricans
groin, axilla
epithelial lesion Associated with insulin resistance or gastric CA
acanthosis nigricans
elevated nodule with central ulceration and telangectasis; + pearly edge
Basal cell CA
Elevated nodule on upper lip and/or non exposed skin
Basal Cell CA
Histology: peripheral palisading
Basal cell CA
Autosomal recessive defect in enzymes for nucleotide excision and repair leading to buildup of pyrimidine dimers in response to sunlight
xeroderma pigmentosum
Ulcerated nodular mass on face or lower lip
squamous cell carcinoma
Precursor to squamous cell ca; hyperkeratotic scaly plaque on face, back or neck
actinic keratosis
Well-differentiated Squamous cell CA; rapid development, spontaneous regression
keratoacanthoma
Cup-shaped tumor filled with keratin debris
keratoacanthoma
Autoimmune melanocyte destruction causing localized loss of skin pigmentation
vitiligo
congenital lack of pigmentation
albinism
Enzyme defect in albinism
tyrosinase -> impaired melanin production
small tan brown macule that darkens with sunlight exposure due to increased number of melanosomes
freckle
mask-like hyperpigmentation of cheeks associated with pregnancy and OCP
melasma
benign melanocyte neoplasm, with hair growth
nevus
Most common cause of death from skin cancer
melanoma
Features of Melanoma
A - symmetry
B - orders are irregular
C - olor is not uniform
D - iameter >6mm
Greatest risk factor for metastasis of melanoma
depth of invasion
melanoma subtype with lentiginous proliferation along ED junction; only radial growth
lentigo maligna melanoma
melanoma subtype involving superficial dermis; with dominant early radial phase
superficial spreading - most common subtype
melanoma subtype with early vertical phase; poor prognosis
nodular
melanoma subtype involving palms and soles, often in dark-skinned individuals
acral lentiginous
Etiologic agents of impetigo
s. aureus, s. pyogenes
erythematous macules, papules on face, with erosions, honey-colored crusts
impetigo
skin infection involving dermis; red, tender, swollen; increased risk with recent surgery, trauma, insect bites
cellulitis
Necrosis of subcutaneous tissue under dermis due to anaerobic bacteria
necrotizing fasciitis
Anaerobic bacteria causes CO2 production under dermi creating “bubbles” (crepitus; subcutaneous emphysema)
necrotizing fasciitis
Etiologic agent of SSSS
S. Aureus
Exfoliative A and B toxins causes lysis of the skin and separation of layers, particularly the stratum granulosum; leads to skin loss
SSSS
Differentiate SSSS and TEN
TEN separation occurs at dermal-epidermal junction
SSSS separation of granulosum
Flesh-colored papiule with rough surface
Verruca
Etiologic agent of Verruca
HPV
Firm, pink umbilicated papule in children, as well as sexually active and immunocompromised adults due to pox virus
Molluscum Contagiosum
Viral inclusions in molluscum contagiosum
molluscum bodies
Skin lesions on pressure points of insensitive areas assoc. with diabetes, syphilis, leprosy, and other neuropathies
neuropathic ulcer
cutaneous tanning caused by local application of heat
erythema ab igne
Clusters of vesicular eruptions following CN V distribution
herpes zoster
Painful, shallow ulcerated acute lesion, self limiting
herpes simplex
Cafe au lait spots, pedunculated and sessile skin lesions, peripheral nerve distribution
neurofibromatosis type I Von Recklinghausen
Diffusely painful subcutaneous fat deposition in middle aged women, around abdomen and thighs
adiposis dolorosa/ Dercum disease
Treatment of recurrent paronychia
wedge resection
treatment of pilonidal sinus
excision (kardyakis procedure with advancement flap)