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!)
Which two ulcerative STDs have PAINFUL initial ulcers?
Chancroid - H. ducreyi (you “do cry” with ducreyi)
Herpes - HSV1/HSV2
Which 3 ulcerative STDs have PAINLESS initial ulcers?
Syphilis - T. pallidum
Granuloma Inguinale / Donovanosis - Klebs granulomatis
Lymphogranuloma venereum - C. trachomatis (has painful “buboes” of coalesced nodes after a painless ulcer)
serotypes and complications (3) of lymphogranuloma venereum
L1-L3 (remember A-C ocular, D-K cause classic STI + inclusion conjunctivitis)
fibrosis
lymph obstruction
anogenital strictures + fistulas
Supernumerary nipples
where? due to what?
anywhere along “embryonic milk line” from axilla to perineum; BILATERAL in 50%
failed involution of mammary ridge
Similarities and differences between “ephelides” (freckles) and SOLAR LENTIGINES?
where found? what are they histologically?
size? in whom?
Both - sun-exposed areas; flat hyperpigmentations (macules)
Ephelides - increased melanin production; smaller; in kids
Solar lentigo - increased melanocyte number; larger; in adults
Topical tx for acne vulgaris
drug and moa
Benzoyl peroxide
becomes benzoic acid which kills Propionibacterium acnes
Topical anti-inflammatory for ACTINIC KERATOSIS
Diclofenac
Topical abx for rosacea
metronidazole
Topical analgesic for postherpetic neuralgia (+ other neuropathic pain)
Capsaicin
activates TRPV1, depletes substance P > nociceptive fiber dysfunction
First-line tx for localized psoriasis (2 things)
- Corticosteroids - DIFLORASONE
2. Vit D analogs - CALCIPOTRIENE / CALCITRIOL (inhibit T cell + keratinocyte proliferation)
Scabies
s/s? where on body? when is it bad + what causes it pathophysiologically?
RAPID spreading PRURITIC rash with RED PAPULES and EXCORIATIONS on the LIMBS
flexor surfaces of wrists, lateral surface of fingers, finger webs
worse at night; type IV HS rxn
most specific finding in scabies
dx?
“linear burrows” - but can be obscured by scratch marks
micro of skin scrapings with mites, ova and feces
infectious causes of SJS? (2)
how long after infection?
CMV
Mycoplasma
1-3 weeks after infection
Leukocytoclastic vasculitis
aka what? causes (2 categories; 5 examples in one)?
cutaneous small vessel vasculitis
- Hepatitis B or C
- Drugs - penicillins, cephalos, sulfonamides, phenytoin, allopurinol
Leukocytoclastic vasculitis (aka cutaneous small vessel vasculitis)
s/s?
NONBLANCHING palpable PURPURA usually on LEGS
shortly after new drug exposure, or with hep B/C
Leukocytoclastic vasculitis (aka cutaneous small vessel vasculitis)
histo
inflamed small vessels with FIBRINOID necrosis
NEUTROPHILS in perivascular infiltrate in first 24 hrs with FRAGMENTED NUCLEI
later mononuclear cells
Vitiligo
histology
partial or complete LOSS OF MELANOCYTES with a complete ABSENCE OF MELANIN
postinflammatory hypopigmentation
what are the 2 mechanisms of hypopigmentation?
- REDISTRIBUTION of existing melanin within skin
2. REDUCED TRANSFER of melanin to keratinocytes
Cafe au lait macules
histo
increased MELANOSOME AGGREGATES within melanocyte cytoplasm
Lentigo
histo
a benign LINEAR MELANOCYTIC HYPERPLASIA
Photoaging
what type of UV?
Mechanism of damage?
What is down- and up-regulated (3)?
Specific collagen + other molecule types?
UV-A penetrates deeper and create…
ROS > inflammatory cell receptor activation
- DECREASED collagen FIBRIL production
- INCREASED production of MMPs (eg, collagenase)
- INCREASED collagen CROSS-LINKS
Degrades TYPE I + III COLLAGEN and ELASTIN
Photoaging
histo
(what happens to epidermis, dermis + junction)
- EPIDERMAL THINNING - corneum dessicates
- FLATTENED RETE RIDGES - at dermoepidermal junction
- in dermis, less fat, vessels, hair follicles, sweat + sebaceous glands
Skin lesion commonly found in Turner or Downs patients
when, where and made of what?
Cystic Hygroma
- at birth
- lymphatic cyst lined with thin endothelium
- posterior neck + lateral chest wall
