Dermatology + STDs Flashcards
actinic keratoses
s/s, histo + association
scaly, red, sandpapery lesions in sun-exposed areas
hyperkeratosis, parakeratosis + atypical keratinocytes
precursor to invasive SCC
basal cell carcinoma
description, histo, progno
sun-exposed areas; low metastatic potential
pearly papules with central depression or ulceration (#1 skin cancer)
nests of basaloid cells and peripheral palisading of nuclei
dermatofibroma
what are they? where are they + how do they look?
“superficial benign fibrous histiocytomas”; benign fibroblast proliferation
usually on legs, as solitary nodules
Kaposi sarcoma
association, appearance
HHV-8 in HIV patient
palpable macules, plaques + nodules; dark brown to violet
3 types of acne vulgaris + their characteristics
comedonal - closed or open comedones on forehead, nose + chin
inflammatory - small red papulse + pustules
nodular - large, painful nodules; sinus tracts + scarring
acne vulgaris pathogenesis
4 elements
hyperkeratinization - with pilosebaceous follicle obstruction
sebaceous gland enlargement - w/ increased sebum
Cutibacterium acnes - metabolizes sebum + releases inflammatory FFAs
follicular inflammation + rupture
acne vulgaris risk factors (5)
androgens - puberty, PCOS
mechanical - excess scrubbing, tight clothes
skin/hair products - oil is comedogenic
excess heat
obesity
Atopic Dermatitis
pathogenesis? clinical s/s? labs?
FILAGGRIN and other epidermal barrier protein defects > increased Ag exposure + hypersensitivity (assoc. with asthma, allergic rhinitis + family history)
intense pruritus
INFANTS - red, crusted lesions extensors + face/scalp/trunk (not diaper area)
ADULTS/KIDS - flexural eczema + lichenification
high IgE and eosinophilia
derma signs in ulcerative colitis (2)
pyoderma gangrenosum - ulcerative rash
erythema nodosum - painful raised red nodules
Langerhans cell histiocytosis
presentation? s/s? tx?
dendritic cell disorder > severe refractory red/ulcerative rash on SCALP, TRUNK, GROIN
infancy or early childhood
flares and resolves without intervention
1 prognostic factor + scales
Melanoma
1 progno = “Breslow depth” - distance from epidermal granular cell layer to the deepest visible melanoma cells
“Clark levels”
1 - only into stratum spinosum; 2 - thru basal layer + BM; 3 - well into papillary dermis; 4 - well into reticular dermis; 5 - into subcutaneous fat
Lentigo maligna
what is it? who has it?
histo? progno?
common pigmented lesions in ELDERLY; sometimes considered “melanoma in-situ” (atypical melanocytes along basilar layer just above BM)
MULTINUCLEATED GIANT MELANOCYTES are characteristic on histo
if it develops into “lentigo maligna melanoma” progno is similar to other melanomas of same stage
Heliotrope rash
how does it look, where is it, and what’s it assoc. with?
red/violet edematous eruption on UPPER EYELIDS and PERIORBITAL SKIN
dermatomyositis
Dermatomyositis
muscle biopsy, associations
PERIMYSIAL leukocytes, patchy ischemia/necrosis, and PERIFASCICULAR atrophy/fibrosis
can occur alone or as paraneoplasia to ADENOCARCINOMAS (more likely if pt develops dermatomyositis after 50)
Pemphigus Vulgaris
auto-Abs, sites, signs, type of WBC
anti-DESMOSOME antibody (desmoglein 1 and 3) deposit INTRAepidermally with EOSINOPHILIC infiltrate
weak, painful flaccid bullae on skin AND MUCOSA (mucosa rare in bullous pemphigoid)
ASBOE-HANSEN positive - bullae spread laterally when pressure is applied
NIKOLSKY positive - new blisters form with gentle traction/rubbing (negative in bullous pemphigoid)
Bullous Pemphigoid
auto-Abs, sites + signs
anti-HEMIDESMOSOME antibody (basement membrane) deposit SUBepidermally
Nikolsky NEGATIVE - new blisters do NOT form with rubbing
ASBOE-HANSEN positive - bullae spread laterally
only skin, no mucosa lesions
Skin lesion differential
Bartonella henselae vs. Mycobacterium marinum vs. Blastomyces dermatitidis
Bartonella - bacillary angiomatosis in immunocompromised; purple tender nodules; bleed if squeezed
M. marinum - wounds inoculated with contaminated water; solitary papule or nodule, eventually ulcer + scarring; granulomatous inflamm. on histo
Blastomyces - verrucous lesions, irregular borders; culture for dx; histo shows granulomas
Wound contracture
when does it happen + via what cells/enzymes
healing by second intention (large wound with irregular borders)
MMPs encourage MYOFIBROBLAST (fibroblasts with ACTIN) accumulation around wound edge; excess MMPs can result in contracture
(MMPs made by fibroblasts, macros, neutros, synovium + some epithelium)
Seborrheic keratosis
who? what? histo? cause? association?
middle-aged to old pts
variable: macule, wart-like tan/brown epidermal tumor; few mm to cm
velvety/greasy surface; well-defined; “stuck-on” look
histo - small basal-like cells, variable pigment, hyperkeratosis (thick corneum) and KERATOCYSTS
cause - maybe FGFR-3 activating mutation
rapid onset of many = LESER-TRELAT SIGN of internal malignancy, often GASTRIC ADC (maybe via IGF-1 from tumor)
Chancroid
microbe, microscopy, features of primary lesion
H. ducreyi
red papules erode into multiple, deep ulcers; yellow-gray base exudate (regional nodes may swell + ulcerate)
organisms clump in long parallel “SCHOOL OF FISH” strands
lesion IS painful (you “do cry” with ducreyi)
Herpes
microbe, microscopy, features of primary lesion
HSV1/2
multiple, small, grouped ulcers; shallow red base
multinucleated giant cells + Cowdry type A bodies (nuclear inclusions) on Tzanck
lesion IS painful
Granuloma Inguinale / Donovanosis
microbe, microscopy, features of primary lesion
Klebs granulomatis
extensive/progressive ulcers with NO node swelling; base may have granulation
deep gram-neg cytoplasmic cysts (Donovan bodies)
lesion NOT painful
Syphilis
microbe, microscopy, features of primary lesion
T. pallidum
single, indurated, well-circ ulcer; clean base
spirochetes on DF
lesion NOT painful
Lymphogranuloma venereum
microbe, microscopy, features of primary lesion
C. trachomatis
small, shallow ulcers; large, painful coalesced inguinal nodes (“buboes”)
cytoplasmic inclusion bodies in epithelium/leukocytes
lesion NOT painful (but nodes are!)
