Derm Flashcards
Acanthosis nigrans
Thickened hyperpigmented zones of skin with a velvet like area usually involving the flexuaral areas( axilia, skin folds of neck, groin,etc)
Benign 80%- ad trait with variable penetrance, associated with obesity and endocrine issues, congenital syndrome; usually appear in childhood or during puberty
Malignant- older adults associated with gastrointestinal adenocarcinoma
Acanthosis
Hyperplasia of the stratum spinosum
Seborrheic keratosis
Middle aged older adults
Coin like plaques tan to dark brown (vary in size)
Horn like cysts on histo (whorls of keratin)
Leser-trelat sign- large numbers of plaques associated with paraneoolastic syndromes / GI carcinoid
Progression of dermatitis
acute (weeping erethymatous rash/spongiosis)–> subactute (crusting over of rash scaling and hyperkeratosis) –> chronic (lichenification from itching, scaling, hyperpigmentation)
Atopic dermatitis
Type 1 IgE mediated hypersentivity
Face in kids, flexor surface (antecubital and popliteal fossa) in adults
Contact dermatitis
Type IV T cell mediated
Metals (nickle), plants (poison ivy), and chemicals (household cleaners, meds)
MC type of contact dermatitis
irritant contact
non immunological rxn; toxic effect of chemical on local skin
Girl playing soccer develops rash on legs, face, and arms, what drug is she on and what is this?
contact photodermatitis
Tetracycline (sulfa, thiazides)
Ring shaped patches of allopecia on scalp with erythema and scaling
Tinea capitus MC in children
- ) Trichophyton tonsurans
- ) Micosporum canis (Woodlamp + )
MC cause of tinea
Trichophyton rubrum
MCC diaper rash and onccyomycosis
candida albicans
High fever, metal confusion, diarrhea, hypotension, erythematous rash associated with a drug rxn
TSS nafcillin
What does actinic keratosis progress to?
Squamous cell carcinoma
What is actinic keratosis associated with?
sun (UVB) damage, arsenic
Where is psorasis most commonly found?
Scalp and pressure areas like the elbow
Development of a rash at areas of trauma
Koebner phenomenon, psoriasis
Munro microabcesses
collection of neutrophils in the stratum corneum (associated with psoriasis)
Single oval shaped scaly pink patch on trunk that develps into papules on the back that follow line of cleavage
pityriasis rosea
herald patch followed by christmas tree distribution
When is psoriasis associated with a destructive arthritis ?
If patient is HLA B27
What population do you see scalded skin syndrome in?
neonates
granulosum layer
no scarring
Atopic triad
atopic dermatitis
allergic rhinitis
asthma
What type of hypersensitivity rxn is pemphigus vulgaris ?
Type II, IgG to desmoglian
What do the basal cells look like on histology in pemphigus vulgaris?
tombstones
What does the dermal epidermal junction look like in lichen planus?
Sawtooth from lymphocytic infiltrate
dermatitis hepatiformis is what type of hypersensitivity rxn?
Type III, IgA and gluten deposition at tips of dermal papilae
What type of antibodies are present in dermatitis hepatiformis?
anti-reticulin antibodies
What is erythema multiforme called when it involves 2 or more mucous membranes?
SJS
How do you get erythema multiforme?
- Disease (mycoplasma, HSV)
- Drugs (sulfa, beta lactams, phenytoin)
- Autoimmune (lupus, preg)
- Cancer
Pathogenesis of acne
Increased keratin of follicular epithelium–> increased sebum production–> propionobacterium acnes / bacterial lipase, cleaves FA and creates further inflammation
most common in adolescents
acne roseacea
inflammatory disease of pilocebateous unit of middle aged people
Can be brought on be heat and alcohol
can evolve into rhinophyma
How does cellulitis spread?
can cause lymphangiitis by elaboration of hylauronidases that let the s. pyogenes infection spread through the subcutaneous tissue
What type of lesion does SLE produce?
skin lesions associated with epidermal atrophy
Pathogenesis of SLE
antibodies to epidermal basement membrane or antiDNA antibody anitigen deposition in basement membrane –> degeneration of basal layer at dermal epidermal junction–>lymphoid infiltrate and atrophic epidermis
Grenz zone
narrow zone beneath the epidermis in leprotamous leprosy that is free of bacteria , under the grenz zone are fomay macrophages with organisms
MCC of inflammation in subcutaneous fat
erythema nodosum
MC malignant tumor of the skin
basal cell carcinoma
Do basal cell carcinomas metastisize?
No
Pearl colored nodule with prominent vascular channels under the surface
basal cell carcinoma
MC cancer associated with immumosuppresive therapy
squamous cell carcinoma
ulcer at orifice of chronically draining sinus that does not improve with antibiotics
squamous cell carcinoma
What is SCC associated with?
XP, immunosuppression, arsenic posioning, sun damage
What is a phenotypic marker for underlying adenocarcinoma of the stomach
acanthosis nigrans
are freckles pre-malignant?
no
flat hyperpigemented lesion of forehead and cheeks in women
pregnancy mask (or OCP use) melasma/chloasma
MC nevi in adults
intradermal nevus
raised papule , pigmented cells only in dermis
nevi all over the body
dysplastic nevus syndrome
precursor to maligancy
MC type of melanoma
Superficial spreading
mostly women over 50, lower extremities and back MC sites,
Malignancy on sun exposed face of elderly people
lentigo maligna
MC type of melanoma in blacks
acral lentigenous melanoma
palms, soles, and subungal (don’t confuse hematoma)
Best system of staging for melanoma
Breslow system
Measured depth
less than 0.76 mm no metastatic potential
greater than 1.7 can metastisize to LNs
Hyperpigmented spots on the skin that when scratched become intensely puritic and red
urticaria pigmentosa
pressure causes mast cells to release histamine which sets up a urticarial rxn
